Table of Contents

EARFCN

EARFCN stands for E-UTRA Absolute Radio Frequency Channel Number. It’s a standardized identifier used in LTE (Long-Term Evolution) and LTE-Advanced cellular networks to uniquely specify the center frequency of a radio channel. Instead of dealing with raw frequencies (e.g., 2140 MHz), network engineers and equipment use EARFCN values for simplicity and consistency.

EARFCN provides a consistent way to reference LTE carrier frequencies globally. FDD (Frequency Division Duplex): Separate EARFCN for UL and DL. TDD (Time Division Duplex): Single EARFCN (UL/DL share frequency).

RSRP

RSRP (Reference Signal Received Power) is a critical measurement in LTE (Long-Term Evolution) and 5G-NR (New Radio) networks that quantifies the signal strength from a cell tower (eNodeB/gNodeB) at your device (UE). It’s essential for network performance, handover decisions, and user experience.

RSRP measures: The average power (in dBm) received from a single cell-specific reference signal (CRS) over a specific bandwidth (typically one resource block ≈ 180 kHz). Focuses only on reference signals—not the entire channel noise or interference.

Typical RSRP Values:

RSRP (dBm)	Signal Quality
> -80 dBm	Excellent (strong)
-80 to -90 dBm	Good
-90 to -100 dBm	Fair (usable)
< -100 dBm	Poor (weak/unstable)
< -120 dBm	No signal

SNR

SNR (Signal-to-Noise Ratio) measures the strength of a desired signal relative to background noise. It quantifies how clearly a signal can be distinguished from interference in communication systems (Wi-Fi, cellular, audio, etc.). SNR is critical for performance—higher SNR means clearer data transmission, fewer errors, and faster speeds.

SNR Range	Performance Impact
> 30 dB	Flawless 4K streaming, low-latency gaming.
20–30 dB	Smooth HD video, fast browsing.
10–20 dB	Basic web browsing; occasional buffering.
0–10 dB	Unstable connectivity; frequent drops.
< 0 dB	Connection lost (noise overwhelms signal).

SNR vs. Related Metrics:

Metric	Focus	SNR Comparison
RSRP	Raw signal strength (LTE/5G).	SNR depends on RSRP—but subtracts noise.
RSSI	Total received power (signal + noise).	SNR = (RSSI – Noise) / Noise.
SINR	Signal vs. noise + interference (more precise).	Often used interchangeably with SNR.

QOS

Explanation of common terms in Vcan2024 QOS

QoS (Quality of Service) is a set of technologies and policies used in networking to prioritize traffic, manage bandwidth, and ensure reliable performance for specific applications, users, or services. It’s critical for maintaining consistent user experiences, especially in networks with limited resources (e.g., cellular, enterprise, or IoT networks).

Key Goals of QoS:

Prioritization: Treat high-importance traffic (e.g., video calls, emergency services) as “VIP” over low-priority traffic (e.g., file downloads).
Resource Allocation: Reserve bandwidth for critical tasks.
Minimize Latency/Jitter: Keep delays low for real-time apps (VoIP, gaming).
Reduce Packet Loss: Ensure data isn’t dropped during congestion.

RSSI

RSSI (Received Signal Strength Indicator) is a measurement of the total received power (signal + noise + interference) in a wireless communication system. It’s a fundamental metric used across Wi-Fi, cellular (LTE/5G), Bluetooth, and IoT networks to gauge raw signal strength—but it does not distinguish between useful signals and noise.

Typically negative values (since dBm is referenced to 1 milliwatt):

-30 dBm: Extremely strong (near transmitter).
-70 dBm: Moderate (reliable connectivity).
<-90 dBm: Weak (unstable or unusable).

Comuart

COMUART refers to a UART (Universal Asynchronous Receiver/Transmitter) interface used for serial communication, typically found in embedded systems, networking hardware, or industrial devices. The “COM” prefix often denotes its role in communication ports (e.g., RS-232, TTL serial).