Cognitive Positioning Systems

Fundamental limits on time delay estimation in dispersed spectrum cognitive radio systems

“…In addition, various modulation schemes have been considered and the effects of unknown channel coefficients and CFOs have been investigated. Cognitive radio systems can employ CRLB information at the transmitter side for achieving range accuracy adaptation [7]. The results of this study indicate that range accuracy can be adapted by selecting an appropriate number (K) of dispersed bands in the spectrum, modulation type, number of observation symbols, and/or SNR levels.…”

“…Cognitive radios with location awareness can support goal-driven autonomous location aware systems, such as location-based services (e.g., package tracking), location-assisted network optimization (e.g., dynamic spectrum management), location-assisted transceiver optimization (e.g., adaptive beamforming), and environment identification (e.g., propagation channel characterization) [4]. The main component of location awareness is to obtain accurate location information [7], [8]. Among various approaches for obtaining location information, time-based techniques are quite popular due to their accuracy and practicality [9], [10].…”

“…Cognitive radio systems with location awareness can use Cramer-Rao lower bound (CRLB) information at the transmitter side to optimize the transmission parameters for achieving goal-driven accuracy requirements. In [7], the CRLB for time delay estimation in multipath channels is derived in the presence of unknown path delays and coefficients. This study is extended in [14] by deriving the frequency-domain CRLB in dynamic spectrum access systems under the assumption that path delays, distance-dependent coefficients, phases and frequency-dependent coefficients are unknown.…”

“…Furthermore, the effects of bandwidth, carrier frequency, and path frequency dependence on the CRLB in dynamic spectrum access systems are investigated via computer simulations. The studies in [7] and [14] are based on the fact that the available bandwidth is in the form of a single piece (i.e., the whole bandwidth). Since the available bandwidths in dynamic spectrum access systems are commonly dispersed [15], a single cognitive radio user can transmit and receive over multiple dispersed bands.…”

Towards a bandwidth efficient cognitive positioning system

“…Bandwidth Determination (BD) and Enhanced Dynamic Spectrum Management (EDSM) [4], which provide adaptive positioning capabilities suited for cognitive radio. The BD model ascertains the amount of bandwidth required to obtain a predefined positional accuracy using the time-of-arrival (TOA) ranging technique.…”