Estimated Performance of a QPRS Radio in the Presence of Frequency Selective Fading.
Abstract
This report provides an estimation of the probability of outage of a QPRS radio (Aventek DR-8A) link in a multipath caused frequency selective fading environment. This performance estimation is based on: (a) A propagation channel model with transfer function of the form H(w) = a(1+b exp (-j(wt+phi)), which has been derived from experimental data. (b) A laboratory simulation of the model with DR-8A radios to determine the range of values of the channel model parameters that degrade raio performance. (c) Assumed probability density functions for the channel model parameters (as random variables), based on sparse experimental data. The experimental data shows that: (a) Radio performance degradation begins (above the flat fade case) with delays (tau in the transfer function) in the order of a few nanoseconds. (b) Longer delays cause increased degradation. (c) For degradation to occur, the function minimum must occur within a few megahertz of the radio passband. The estimated probability of the fade outage (based on measured parameters of the DR-8A radio), indicate that: (a) The predicted outage for distances greater than 25 miles is higher than that predicted using flat fade methods. (b) Space diversity alone may not provide sufficient performance improvement at distances must beyond 30 miles, although the combination of space diversity and adaptive equalizer should be adequate for nearly all line-of-sight paths. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1981
- Accession Number
- ADA102114
Entities
People
- Stephen T. Matsuura