THE OPERATIONAL VALIDATION OF THE CURTS CONCEPT USING 2400-BAUD AUTODIN.

Abstract : The second and concluding report is made of a test that was designed to validate the quantitative improvement (over normal procedures) obtained by the CURTS (Common User Radio Transmission Sounding) Phase 2 Automatic Frequency Selection System. The system directed frequency changes on three DCS trunks--Okinawa, Guam, and McClellan--terminating at Hickman Air Force Base, Hawaii. Major conclusions of the experiment are: (1) The results of this test have validated the success of the CURTS concept for operational DCS use. (2) The CURTS Phase II system was capable of directing frequency changes with a minimal amount of human interpretation. (3) The CURTS system has proved itself superior to normal frequency control procedures by: (a) improving average throughput between 4.5 percent and 9 percent at the above-90 percent level; (b) reducing the standard deviation of throughput by approximately one-half; (c) increasing user availability by 13.6 percent to 22 percent to achieve a user availability of close to 95 percent at the 90 percent throughput level; and (d) structuring frequency resources to achieve an improvement in user availability of 18.3 percent, in addition to that obtained by real-time frequency selection in (c). (4) When good frequency selection procedures are employed with an adequate complement of frequencies, the benefits of forward error correction are, at most, minimal. (5) The number and duration of outages attributable to propagation have been greatly exaggerated. (Author)