QPSK (Quadrature Phase Shift Keying)

Quadrature Phase Shift Keying encodes two bits per symbol by selecting between four phases of the carrier wave. QPSK offers a good balance of spectral efficiency and noise tolerance, and is widely used in satellite communications, LTE/5G control channels, and many other systems where robust transmission matters more than peak data rate.

Categories: Radio Access NetworkEncryption and Cryptography

QPSK in context

The radio access network is where mobile devices attach to the operator's infrastructure. Attacks in this layer include IMSI catching, rogue base stations and downgrade attacks; defenses rest on mutual authentication, integrity-protected signaling and Open RAN supply-chain hygiene.

Cryptography in telecom spans air-interface ciphers (A5/1, A5/3, ZUC, SNOW, NEA/NIA), transport (IPsec, TLS) and identity (AKA, 5G-AKA, EAP-AKA'). Weak or downgradeable ciphers remain a live risk on 2G/3G fallback.

To place QPSK in the wider telecom-security picture, review AP, Broadband, CDMA, HTTPS, Jitter and MAC — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

More from the TelcoSec Glossary

Browse the full TelcoSec Glossary, the Ultimate Guide to Mobile Network Security, or the P1 Arsenal of telecom-security tools.