ETSI standard EN301 893 V1.7.1, the European Union’s harmonized radio standard for unlicensed devices operating in the 5150~5350 MHz and 5470~5725 MHz frequency bands, has DFS requirements. It specifies the types of radar waveforms that devices operating in 5250~5350 MHz and 5470~5725 MHz should be able to detect. The detailed parameters are listed in the table below.
Radar type 1~4 are constant PRF based signals. Radar type 4 uses a chirp signal with ±2.5 MHz frequency deviation. Radar type 5 and 6 are single pulse based staggered PRF radar test signals using 2 or 3 different PRF values, see Figure 1. For radar type 5, the difference between the PRF values shall be between 20 and 50 Hz. For radar type 6, the difference shall be between 80 and 400 Hz.
| Radar Type | Pulse Width (μs) | Pulse Repetition Frequency PRF(Hz) | Number of Different PRFs | Number of Pulses per Burst |
|---|---|---|---|---|
| Ref. | 1 | 700 | 1 | 18 |
| 1 | 0.5~5 | 200~1000 | 1 | 10 |
| 2 | 0.5~15 | 200~1600 | 1 | 15 |
| 3 | 0.5~15 | 2300~4000 | 1 | 25 |
| 4 | 20~30 | 2000~4000 | 1 | 20 |
| 5 | 0.5~2 | 300~400 | 2 or 3 | 10 |
| 6 | 0.5~2 | 400~1200 | 2 or 3 | 15 |
Figure 1. General Structure of a Multiple Burst/Constant PRF Based Radar Test Signal
Figure 2. General Structure of a Single Burst, Which is a Pulse Based Stagger PRF Radar Test Signal (Source: ETSI EN 301 893 V1.7.1)
Figure 3. General Structure of a Single Burst, Which is a Packet Based Stagger PRF Radar Test Signal (Source: ETSI EN 301 893 V1.7.1)