Providing multimedia communications services from high altitude platforms

Abstract

SUMMARYSystem level design considerations for high altitude platforms operating in the mm-wave bands are examined. Propagation e!ects in these bands are outlined, followed by a brief introduction to di!erent platform scenarios. Ground-based and platform-based "xed wireless access scenarios are considered, and it is shown that using a platform, a single base station can supply a much larger coverage area than a terrestrial base station. The e!ects on performance of platform displacement from its desired location with both "xed and steerable antennas are also examined. It is shown that steerable antennas are of most use when "xed stations are immediately below the platform, with no bene"t for "xed stations on the edge of coverage. The bandwidths required to serve several tra$c distributions (suburbs and city centre based) are evaluated using the Shannon equation. It is shown that capacity can be constrained when users are located in the city centres, despite longer line of sight paths to users out in the suburbs. The e!ects of temporal changes in the spatial tra$c distribution are investigated. It is shown that bandwith requirements can be reduced if the platform moves to track these changes.

Improving the system capacity of broadband services using multiple high-altitude platforms

“…The remaining HAPs are designated the interfering HAPs (i.e., the set ). Thus, the at an arbitrary point on the coverage area can be calculated as (1) where is the transmission factor taking into account the link length, transmitter power, etc., from one of the set of interfering HAPs. Losses are assumed to increase with the square of the link length [8], as propagation is line-of-sight at these frequencies;…”

“…W ITH AN EVER increasing demand for capacity for future generation multimedia applications, service providers are looking to utilize the frequency allocations in the millimeter wave bands [1]. In these frequency bands, line-of-sight paths are required and signals are strongly attenuated by rain [2], [3].…”

“…HAPs can also accommodate longer link lengths with less rain attenuation than would be associated with similar terrestrial links. Such platforms will have a rapid roll-out capability and the ability to serve a large number of users, using considerably less communications infrastructure than required by a terrestrial network [1]. To aid the eventual deployment of HAPs the ITU has recently allocated spectrum around 48 GHz worldwide [13] and 31/28 GHz for certain Asian countries [14], with spectrum in the 3G bands also allocated for use with HAPs [15].…”

On the capacity of multicell coverage MIMO systems in High Altitude Platform channels

“…In this paper the capacity performance of a general multi cell coverage system is investigated under both the Rayleigh and the HAPs channel models through extensive Monte Carlo (MC) simulations. The first channel model, that is the Rayleigh channel model, is considered as a typical channel model for Non Line of Sight (NLoS) terrestial communications and a HAPs channel [5]. The rest of the paper is organized as follows.…”

Space-Time Diversity Techniques for WCDMA High Altitude Platform Systems

“…However, owing to the amount of new infrastructures required, it will still be some time before 3G is ubiquitous, especially in developing countries. One possible cost effective solution for deployments in these areas is to use High Altitude Platforms (HAPs) (Collela et al, 2000;Djuknic et al, 1997;Grace et al, 2001;Miura & Oodo, 2002;Park et al, 2002;Steele, 1992;Thornton et al, 2001;) for delivering 3G (WCDMA) communications services over a wide coverage area (Dovis et al, 2002;Falletti & Sellone, 2005;Foo et al, 2000;Masumura & Nakagawa, 2002;Vazquez et al, 2002). HAPs are either airships or planes that will operate in the stratosphere, 17-22 km above the ground.…”