WiMAX Forum

Description

The WiMAX Forum is not a 3GPP technology itself, but an external organization whose specifications are referenced within 3GPP standards to enable interoperability with WiMAX networks. WiMAX, based on IEEE 802.16 standards, is a broadband wireless access technology. Within 3GPP, the forum's role is critical for defining how WiMAX networks can be integrated as a trusted non-3GPP access network into the Evolved Packet Core (EPC). This integration allows mobile operators to leverage WiMAX for data services alongside their 3GPP LTE/5G networks.

The architectural integration involves the WiMAX network acting as an access network connected to the EPC via specific interfaces. For a trusted WiMAX access, the network includes elements like the Access Service Network (ASN) and Connectivity Service Network (CSN), which interface with the 3GPP Packet Data Network Gateway (PDN GW) and the 3GPP Authentication, Authorization, and Accounting (AAA) server. The WiMAX Forum specifications ensure that these WiMAX network elements comply with the protocols and procedures required by 3GPP for secure authentication, IP address allocation, and policy enforcement.

The key technical aspects covered by referencing WiMAX Forum documents include the definition of the trusted access point name, the protocols for establishing the data path (e.g., using Proxy Mobile IP version 6 or GRE tunnels), and the mechanisms for user authentication (e.g., based on EAP methods). The WiMAX Forum certification ensures that WiMAX products meet these interoperability requirements, guaranteeing that a device or network gateway from one vendor can connect seamlessly to a 3GPP core network from another vendor. This standardization is vital for creating a unified service experience across heterogeneous access technologies.

Purpose & Motivation

The purpose of referencing the WiMAX Forum in 3GPP specifications is to formally support the interworking between 3GPP mobile core networks and WiMAX wireless broadband networks. Historically, mobile networks (2G, 3G) and fixed wireless broadband networks operated in separate silos. The evolution towards an all-IP core network (the EPC) in 3GPP Rel-8 created an opportunity to unify access, allowing operators to offer services over any IP-based access technology, including WiMAX.

This addressed a significant business and technical problem: operators who deployed both 3GPP and WiMAX networks needed a way to offer seamless mobility and consistent policy control across these different access types. Without standardized interworking, users would have separate subscriptions, different authentication methods, and disjointed service experiences. By adopting the WiMAX Forum's certified specifications, 3GPP ensured that WiMAX could be integrated as a 'trusted' access, meaning the core network could apply the same security, QoS, and charging policies as it does for LTE access. This enabled converged service offerings and more flexible network deployment strategies for operators.