The depolarization effects of Earth-Space link at MMW Bands
The depolarization effects of Earth-Space link at MMW Bands and their mechanisms are analysed. The models to evaluate XPD induced by clear atmosphere, rain, ice crystals, snow, sand-dust storm and ionized layer are summarized and analysed. The methods to calculate total XPD including the influence of transmitting antenna are discussed. The results given in this paper are important for frequency resue and depolarization MIMO techniques.
Dual-polarized channel outages during multipath fading
A statistical model for outages that occur in a dual-polarized-frequency radio channel during periods of multipath fading is proposed, and an analytical expression for outage time obtained. The model, which results in Rice-Nakagami statistics for the cochannel interference signal, describes channel outage time as a function of several environmental and radio-system parameters. The formulation obtained allows for efficient parameteric studies to evaluate the importance of these parameters to channel outage time and to examine parameter sensitivity questions. Results of practical significance relative to hardware xpd requirements, maximum hop length, system gain, dependence on geographic environment, and digital terminal performance characteristics are obtained for present 11-GHz QCPSK (quaternary-coherent-phase-shift-keyed) digital radio systems. Estimates of dual-polarized-frequency channel outage time are obtained for a variety of representative system parameter values and compared with expected outage times for a conventional channel. Particular attention is given to the mechanism of channel outages during multipath fading, and several potential means for control and/or reduction of channel outage time are discussed.
Error rate considerations for coherent phase-shift keyed systems with co-channel interference
In this paper we present a theoretical analysis of the performance of an m-phase coherent phase-shift keyed system in the presence of random gaussian noise and interference. An explicit expression is given for the probability of error of the phase angle of the received signal; we show that this probability of error can be expressed as a converging power series. We show that the coefficients of this series are expressible in terms of well-known and well-tabulated functions, and we give methods of evaluating the character error rates of the systems. We also show that this error rate is minimum when all the interference power is concentrated in a single interferer, and that it attains its maximum [P m ] max when the total interference power is equally distributed amongst the K interferers. The limiting case when K goes to infinity is considered. The cases of K = 1, and m = 2, 4, 8, and 16 are treated in some detail, and the results are given graphically. The usefulness of the results presented in this paper is that the designer can have at his disposal very simple expressions with which to evaluate the performance of any given Coherent Phase-Shift Keyed system when the received signal is corrupted by both interference and random gaussian noise.