Cognitive spectrum utilization in Ka band multibeam satellite communications

Abstract

Multibeam satellite networks in Ka band have been designed to accommodate the increasing traffic demands of the coming years. However, these systems are spectrum limited due to the current spectrum allocation policies. This paper investigates the potentials of applying cognitive radio techniques in satellite communications in order to increase the spectrum opportunities for future generation of satellite networks without interfering operation of incumbent services. These extra spectrum opportunities can potentially amount to 2.4 GHz of bandwidth in downlink, and to 2 GHz of bandwidth in uplink for high density fixed satellite services (HDFSS).

Cooperative power and DoT estimation for a directive source

“…Therefore, in order to solve (6) optimally, a line search over φ as in Theorem 2 is sufficient to find the optimal φ, and consequently the optimal P s using the expression in Theorem 1.…”

“…While this assumption may be valid in the lower part of the spectrum such as the TV whitespace, due to the directive nature of communications in the higher part of the spectrum (e.g. fixed-service terrestrial or satellite links in 18 GHz and above [6]), the developed algorithms may fail to achieve a good accuracy. Therefore, in order to obtain a reliable spectrum map, it is necessary to estimate the direction of transmission (DoT) (i.e., the direction of antenna with the maximum gain) as well as the location and the transmitted power.…”

GEO Satellite Feeder Links and Terrestrial Full-Duplex Small Cells: A Case for Coexistence

“…This has led to the acquisition of exclusive frequencies as well as an exploration of co-existence of the two systems. Dynamic or uncoordinated spectrum utilization employing cognitive radios enable such a co-existence by letting the cognitive user utilize the spectrum of the incumbent user without prior regulatory coordination and waiving right of interference protection, conditioned on not imposing harmful interference to the incumbent user [1]. The idea of coexistence of satellite networks with other services is considered in a number of recent works [1] − [6].…”

“…Dynamic or uncoordinated spectrum utilization employing cognitive radios enable such a co-existence by letting the cognitive user utilize the spectrum of the incumbent user without prior regulatory coordination and waiving right of interference protection, conditioned on not imposing harmful interference to the incumbent user [1]. The idea of coexistence of satellite networks with other services is considered in a number of recent works [1] − [6]. These works typically deal with coexistence scenarios involving satellite downlink/ uplink and terrestrial cellular networks, [2], [6] or satellite uplink with downlink of fixedsatellite-services (FSS) [3].…”

“…Such feeder links in the licensed Ka-band, like the broadcasting-satellite-service (BSS) uplinks in 17 − 40 GHz, use highly directive antennas thereby encouraging spatial reuse of the frequencies by cognitive users. Further, short range small cells 1 planned to operate around the Ka-band, employ low-power transmissions [7]; such transmissions can not reach the distant in-orbit GEO 1 Significance of small cells in providing improved cellular coverage, capacity and applications for homes and enterprises as well as metropolitan and rural areas is well-known [8].…”