Android permissions

Location permission. Cellular and wifi scan functions need this permission. Without it many parts of the app may not work correctly.

Phone permission. It is essential for gathering phone and network state. Most of the app will not work without this permission.

Tech Notes:

Signal

WiFi -95dBm to -35dBm
GSM -113dBm to -51dBm
CDMA -100dBm to -75dBm
EVDO -105dBm to -65dBm
LTE -140dBm to -43dBm
5G -140dBm to -43dBm

Networks

2G - GPRS, EDGE, CDMA, IDEN
3G - HSPA, HSUPA, HSDPA, EHRPD, 1XRTT, EVDO, UMTS, HSPA+
4G - LTE, LTE+
5G - New generation radio NR

Technologies

[GSM] - Global System for Mobile Communications. 2G GSM network
[CDMA] - Code Division Multiple Access. 2G CDMA network
[EDGE] - Enhanced Data GSM Environment. 2G GSM network
[HSPA] - High Speed Packet Access. 3G GSM network
[HSUPA] - High Speed Uplink Packet Access. 3G GSM network
[HSDPA] - High Speed Downlink Packet Access. 3G GSM network
[EHRPD] - Evolved High Rate Packet Data. 3G CDMA network
[1xRTT] - CDMA Data Mode. 3G CDMA network
EVDO - Evolution Data Optimized. 3G CDMA network.
[UMTS] - Universal Mobile Telecommunications System. 3G GSM network
[HSPA+] - Evolved HSPA. 3G GSM network
[LTE] - Long Term Evolution. 4G network
[LTE+] - LTE-Advanced and LTE-Advanced Pro. 4G network
[CDMA/EVDO Ec/Io] - This is a measure of the quality of your CDMA/EVDO channel.
[LTE RSRP] - Reference Signal Received Power.
[LTE RSRQ] - Reference Signal Received Quality.
[IWLAN] - Mobile offloading. The carrier is using your WiFi to offload cellular functions
[5Ge] - Advanced pro LTE (not real 5G)
[Sub-6] - NR (5G) for 5G Sub-6 networks
[5G+/NR] - 5G+/5G Ultra Wideband - 5G mmWave

Note - If you have a good signal strength but poor quality then your connection will also be poor.