Съдържание

EARFCN

EARFCN означава E-UTRA Absolute Radio Frequency Channel Number. It’s a standardized identifier used in LTE (Long-Term Evolution) и 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 (Дуплекс на честотно разделение): Separate EARFCN for UL and DL. TDD (Дуплекс от време на време): Single EARFCN (UL/DL share frequency).

RSRP

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

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

Typical RSRP Values:

RSRP (стока)	Качество на сигнала
> -80 стока	Отличен (силен)
-80 да се -90 стока	добре
-90 да се -100 стока	Fair (usable)
< -100 стока	беден (weak/unstable)
< -120 стока	No signal

SNR

SNR (Съотношение сигнал/шум) 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, клетъчен, звуков, и т.н.). SNR is critical for performance—higher SNR means clearer data transmission, fewer errors, and faster speeds.

SNR диапазон	Performance Impact
> 30 децибела	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 децибела	Connection lost (noise overwhelms signal).

SNR vs. Related Metrics:

Метрика	фокус	SNR Comparison
RSRP	Raw signal strength (LTE/5G).	SNR depends on RSRP—but subtracts noise.
RSSI	Total received power (сигнал + шум).	SNR = (RSSI – Шум) / Шум.
Sinr	Signal vs. шум + намеса (more precise).	Often used interchangeably with SNR.

QOS

Explanation of common terms in Vcan2024 QOS

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

Key Goals of QoS:

Приоритизиране: Treat high-importance traffic (e.g., video calls, аварийни служби) 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, игри).
Reduce Packet Loss: Ensure data isn’t dropped during congestion.

RSSI

RSSI (Индикатор за силата на получения сигнал) is a measurement of the total received power (сигнал + шум + намеса) in a wireless communication system. It’s a fundamental metric used across Wi-Fi, клетъчен (LTE/5G), Bluetooth, and IoT networks to gauge raw signal strength—but it does not distinguish between useful signals and noise.

Обикновено negative values (since dBm is referenced to 1 миливат):

-30 стока: Extremely strong (near transmitter).
-70 стока: Умерен (reliable connectivity).
<-90 стока: слаб (unstable or unusable).

Comuart

COMUART се отнася до a UART (Универсален асинхронен приемник/предавател) interface used for серийна комуникация, typically found in embedded systems, networking hardware, or industrial devices. Най- “COM” prefix often denotes its role in communication ports (e.g., RS-232, TTL сериен).