Assignment Fidelity
Understanding Assignment Fidelity
When a telecom carrier receives a spectrum license, they are authorized to transmit on specific frequencies, at specific power levels, within specific bandwidths. Assignment fidelity measures how faithfully the actual transmission matches these authorized parameters. Poor fidelity means interference with neighboring operators — and potentially, loss of the license.
The Parameters of Fidelity
Assignment fidelity encompasses multiple dimensions:
- Frequency accuracy: The carrier must sit precisely on the assigned center frequency. Modern 5G base stations use GPS-disciplined oscillators to maintain frequency accuracy within ±50 parts per billion.
- Bandwidth compliance: The signal must not spread beyond the authorized channel bandwidth. Digital predistortion and baseband filtering ensure occupied bandwidth stays within limits.
- ACLR: Adjacent Channel Leakage Ratio measures how much signal power leaks into neighboring channels. 5G NR requires ≥45 dB ACLR at the first adjacent channel.
- Power compliance: The effective radiated power must not exceed the authorized maximum.
Key Equations
Assignment Fidelity in spectrum management and radio regulatory compliance refers to the degree to which a radio transmitter's actual emission characteristics conform to the parameters...
Key specifications:
45 dB
Qubit: |ψ⟩ = α|0⟩ + β|1⟩, |α|²+|β|²=1
Comparison
| Aspect | Assignment Fidelity Spec | Typical Range | Impact | Design Note |
|---|---|---|---|---|
| Primary function | Regulatory authorities (FCC, Ofcom, ACMA... | Application-dep. | Critical | Verify in sim |
| Operating range | Understanding Assignment Fidelity When a... | Application-dep. | Critical | Verify in sim |
| Performance | Assignment fidelity measures how faithfu... | Application-dep. | Critical | Verify in sim |
| Integration | Poor fidelity means interference with ne... | Application-dep. | Critical | Verify in sim |
| Trade-off | The Parameters of Fidelity Assignment fi... | Application-dep. | Critical | Verify in sim |
Frequently Asked Questions
How is assignment fidelity measured in the field?
Regulatory enforcement agencies use spectrum monitoring equipment — typically a calibrated spectrum analyzer with a directional antenna aimed at the transmitter. The measurement captures the carrier frequency (compared against the licensed frequency), the occupied bandwidth (measured at –26 dB points per ITU-R SM.443), out-of-band emissions, and effective radiated power (calculated from the measured power spectral density, antenna gain, and measurement distance).
What causes poor assignment fidelity?
Common causes include: oscillator drift due to temperature variations or aging (causing frequency offset), amplifier nonlinearity (causing spectral regrowth that violates bandwidth and ACLR limits), antenna system faults (causing power level deviations), and software configuration errors (wrong channel bandwidth or center frequency programmed). Modern base stations include continuous self-monitoring that detects and compensates for most of these issues automatically.
What are the consequences of non-compliance?
Regulatory consequences escalate: initial warning and requirement to correct the issue within a specified timeframe, monetary fines (FCC fines can reach hundreds of thousands of dollars), forced power reduction or shutdown of the non-compliant transmitter, and ultimately, license revocation. Beyond regulatory action, non-compliant transmissions cause interference to adjacent operators, potentially triggering commercial liability claims.