Tropospheric Scatter System Using Angle Diversity

URSI National Committee Report: Commission 2. Tropospheric Radio Propagation

“…An aspect of single scatter theory which is receiving increased attention lately is angle diversity [Bolgiano, 1958c;Vogelman, 1959]. This is intimately related to the concept of antenna coupling loss developed earlier [Booker, 1955;Staras, 1957Staras, , 1959bHartman, 1959].…”

Βελτιστοποίηση Και Αξιολόγηση Της Επίδοσης Ασύρματων Ψηφιακών Συστημάτων Επικοινωνίας Με Πολλαπλές Κεραίες Εκπομπής Και Λήψης

“…Alternatively, FH-SS technology utilizes bandwidth expansion to exploit the inherent frequency diversity of the channel. 27 Finally, a DS-SS system employing a rake receiver is capable of resolving multipath components at different time delays, a phenomenon also called multipath diversity. 28…”

“…26 Frequency interleaving is the mapping of the coded bits to the subcarriers (bit distribution in the frequency domain). 27 Håkan Olofsson et al (1995) showed that FH-SS also introduces interference diversity, since different signals interfering with the desired one at different times can result in an averaging effect which improves performance in system level. 28 The rake receiver, proposed by Robert Price and Paul Green (1958), uses several correlators or fingers, each assigned to a different multipath component, to separate and coherently combine all the delayed replicas of the wideband signal.…”

“…Friis and Feldman (1937) [25] exploited this phenomenon with the aid of a special arrangement whereby individual wave groups arriving at different vertical angles were received separately and, after delay equalization, combined coherently to offer directional diversity or directivity diversity. 34 Later, Vogelman et al (1959) [27] extended the concept of a single beam steerable to a multibeam antenna, where signal components associated with individual beams were particularly 30 This implies that (L − 1)T ≥ Tc ⇒ L ≥ (Tc/T ) + 1. 31 The diversity order provided by channel coding is directly related to the minimum Hamming distance of the codes.…”

“…Consequently, we will proceed with the replacement of the waveform-based channel model by a discrete-time one, assuming either perfect equalization or flat fading channel conditions. 27 Under this consideration, we may further simplify (2.28) by setting L p = 1 and defining h (m) 1 h (m) and τ 1 τ , which finally takes the form…”