| 455 / | HD | TELECOMMUNICATIONS |
| 403 | DF | RADIOTELEPHONE SYSTEM {12} |
| 422 | DF | .~ Zoned or cellular telephone system {14} |
| 450 | ![]() | .~.~ Channel allocation {4} |
| 451 | DF | .~.~.~> Hybrid allocation |
| 452 | DF | .~.~.~> Dynamic allocation |
| 453 | DF | .~.~.~> Load balancing |
| 454 | DF | .~.~.~> Spectrum sharing for different type of system (e.g., point-to-point microwave, television, etc.) |