OFDM (Orthogonal Frequency Division Multiplexing)

Orthogonal Frequency Division Multiplexing divides a wideband channel into many narrow orthogonal subcarriers, each carrying a low-rate stream. The technique is robust against multipath fading and is the basis of LTE downlink, 5G NR (both up and downlink with CP-OFDM), Wi-Fi (802.11a/g/n/ac/ax), and DVB. 5G adds flexible numerology with multiple subcarrier spacings to support diverse use cases.

Categories: Radio Access NetworkInternet and Routing

OFDM in context

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

Telecom networks depend on Internet-style routing (BGP, DNS, MPLS) for interconnect, transport and application delivery. Route hijacks and DNS abuse can degrade or intercept signaling as easily as any application-layer attack, which is why RPKI and DNSSEC are now standard hardening for carrier networks.

To place OFDM in the wider telecom-security picture, review OFDMA, CDMA, TDMA, FDD, LTE-Advanced (LTE-A) and BSS.

Related terms

Related topic hubs

  • Diameter Security 4G/LTE Diameter threats across IPX/roaming and DEA defenses.
  • Diameter Attacks S6a IDR/PUR/CLR abuse, subscriber tracking, LTE signaling attacks.
  • 5G Security 5G SBA, SEPP, SUCI, 5G-AKA, N32 and service-based interface security.
  • 5G NEF Security Network Exposure Function security in the 5G core.

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.