Terminology » UWB BPRF vs HPRF: Key Differences & Technical Comparison

UWB BPRF vs HPRF: Key Differences & Technical Comparison

Introduction : One of the most fundamental configuration choices in modern UWB design is selecting the right Pulse Repetition Frequency (PRF). The distinction between Base Pulse Repetition Frequency (BPRF) and High Pulse Repetition Frequency (HPRF) is not just about speed; it dictates your device’s security capabilities, power profile and compatibility with legacy networks. In this comparison, we analyze the architectural differences between BPRF and HPRF within the IEEE 802.15.4z/ab standards. The fundamental difference lies in density of pulses transmitted over time.

BPRF (Base Pulse Repetition Frequency)

Mean PRF: Fixed at 62.4 MHz.
Usage in 802.15.4ab: It is used for robust, lower data rate modes (DRBM_LP and DRBM_HP).
Characteristics: Because it sends fewer pulses, it generally consumes less active power during the preamble processing in some architectures, but it has lower maximum data throughput. It is essential for backward compatibility with older UWB devices.

HPRF (High Pulse Repetition Frequency)

Mean PRF: Higher options of 124.8 MHz and 249.6 MHz.
Usage in 802.15.4ab: It is the foundation for the Enhanced Modulation (HRP-EMDEV). It powers the new “Long Range” modes (1.95 Mbps) and “High Speed” modes (up to 124.8 Mbps).
Characteristics: By packing more pulses into the same timeframe, HPRF allows for:
- Higher Data Rates: Up to 124.8 Mbps (using very short symbol times).
- Better Link Budget: More pulses allow for better integration gain at the receiver.
- Secure Ranging: HPRF is required for the Scrambled Timestamp Sequence (STS) used in secure ranging to prevent distance spoofing.

Key Comparison between BPRF and HPRF

Feature	BPRF	HPRF
Mean PRF	62.4 MHz	124.8 MHz or 249.6 MHz
Peak PRF	499.2 MHz	249.6 MHz or 499.2 MHz
Max. Data Rate (4ab)	6.8 Mbps	124.8 Mbps
Min. Data Rate (4ab)	0.9 Mbps	1.95 Mbps
Symbol Times	Medium to Long	Extremely short (8 ns) to very long (512 ns)
Coding Schemes	Typically CL3	CL3, CL7 and Optional LDPC
Primary use case	Legacy compatibility, basic data, power saving	High speed video/audio, secure ranging (STS), enhanced long range
Pulses per symbol	Typically 8 or 64	Flexible: 2,4,8,16 or 64

Summary: While BPRF remains relevant for backward compatibility and basic communication, HPRF is the clear future of the UWB ecosystem. Its higher pulse density is the enabler for Scrambled Timestamp Sequences (STS), essential for secure car access and the high speed data modes of 802.15.4ab. HPRF is used for secure ranging, video streaming speed or maximum penetration (long range).