Índice

EARFCN

EARFCN significa E-UTRA Absolute Radio Frequency Channel Number. It’s a standardized identifier used in LTE (Long-Term Evolution) e LTE-Advanced cellular networks to uniquely specify the center frequency of a radio channel. Instead of dealing with raw frequencies (por exemplo., 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 (Divisão de frequência duplex): Separate EARFCN for UL and DL. TDD (Divisão de tempo duplex): Single EARFCN (UL/DL share frequency).

RSRP

RSRP (Reference Signal Received Power) is a critical measurement in LTE (Long-Term Evolution) e 5G-NR (New Radio) networks that quantifies the sinal de força from a cell tower (eNodeB/gNodeB) at your device (UE). It’s essential for network performance, handover decisions, e experiência do usuário.

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

Typical RSRP Values:

RSRP (dBm)	Qualidade do sinal
> -80 dBm	Excelente (Forte)
-80 para -90 dBm	Boa
-90 para -100 dBm	Fair (usable)
< -100 dBm	Pobre (weak/unstable)
< -120 dBm	Sem sinal

SNR

SNR (Relação sinal / ruído) 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, celular, auditivo, etc.). SNR is critical for performance—higher SNR means clearer data transmission, fewer errors, and faster speeds.

Faixa SNR	Performance Impact
> 30 dB	Flawless 4K streaming, low-latency gaming.
20–30dB	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:

Métrica	Foco	SNR Comparison
RSRP	Raw signal strength (LTE/5G).	SNR depends on RSRP—but subtracts noise.
RSSI	Total received power (sinal + barulho).	SNR = (RSSI – Barulho) / Barulho.
Sinr	Signal vs. barulho + interferência (more precise).	Often used interchangeably with SNR.

QoS

Explanation of common terms in Vcan2024 QOS

QoS (Qualidade de serviço) is a set of technologies and policies used in networking to prioritize traffic, manage bandwidth, e ensure reliable performance for specific applications, Comercial, or services. It’s critical for maintaining consistent user experiences, especially in networks with limited resources (por exemplo., celular, enterprise, or IoT networks).

Key Goals of QoS:

Priorização: Treat high-importance traffic (por exemplo., chamadas de vídeo, emergency services) como “VIP” over low-priority traffic (por exemplo., file downloads).
Resource Allocation: Reserve bandwidth for critical tasks.
Minimize Latency/Jitter: Keep delays low for real-time apps (VoIP, jogos).
Reduce Packet Loss: Ensure data isn’t dropped during congestion.

RSSI

RSSI (Indicador de Intensidade do Sinal Recebido) is a measurement of the total received power (sinal + barulho + interferência) in a wireless communication system. It’s a fundamental metric used across Wi-Fi, celular (LTE/5G), Bluetooth, and IoT networks to gauge raw signal strength—but it does not distinguish between useful signals and noise.

Tipicamente negative values (since dBm is referenced to 1 miliwatt):

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

Comuart

COMUART refere-se a um UART (Receptor/transmissor assíncrono universal) interface used for comunicação serial, typically found in embedded systems, networking hardware, or industrial devices. o “COM” prefix often denotes its role in communication ports (por exemplo., RS-232, Série TTL).