Home Wireless Local Area Network

Description

Home WLAN refers to a Wireless Local Area Network that is interworking with the Home Public Land Mobile Network (HPLMN) of a 3GPP-WLAN interworking user. This concept is defined in 3GPP specifications 22.234, 22.934, and 23.234. It is part of the broader 3GPP-WLAN interworking framework, which enables mobile operators to extend their services over WLAN access networks. The Home WLAN is essentially the WLAN that is owned or partnered by the home operator and integrated with the HPLMN to provide services such as access to the operator's IP core, seamless mobility, and unified authentication. When a subscriber is within range of a Home WLAN, they can connect to it and access 3GPP services as if they were on the cellular network, often with better indoor coverage and higher data rates.

The architecture for Home WLAN interworking involves several key components. The WLAN Access Network consists of WLAN Access Points (APs) and possibly a WLAN Access Controller (AC). The WLAN interworking with the HPLMN is facilitated through the WLAN Access Gateway (WAG), Packet Data Gateway (PDG), and the Authentication, Authorization, and Accounting (AAA) server. The WAG acts as a gateway for user data between the WLAN and the 3GPP network, while the PDG provides secure tunnel termination and IP address allocation. The AAA server, typically a 3GPP AAA server, authenticates the user based on their subscription credentials (e.g., SIM-based authentication) and authorizes access to services. The interface between the WLAN and the 3GPP network may be based on the Wn, Wp, Wa, and Wu interfaces as defined in 3GPP specifications.

How it works: When a UE with WLAN capabilities enters the coverage of a Home WLAN, it discovers the network and initiates association. The UE then performs authentication with the 3GPP AAA server using EAP-AKA or EAP-SIM, leveraging the credentials stored in the UICC. Upon successful authentication, the UE may establish a connection to the PDG via the WAG, creating a secure tunnel (e.g., IPsec) for user plane traffic. The PDG allocates an IP address to the UE, and the traffic is routed through the HPLMN's core network. This allows the UE to access operator services, such as IMS, and the internet with the same policies and charging as cellular access. The Home WLAN can be integrated with the cellular network for seamless handover, although this requires additional features like mobility management and policy control.

The Home WLAN concept is important for operators because it allows them to offload traffic from cellular networks, especially in indoor environments where WLAN is prevalent. It also enables them to offer competitive services and improve coverage. The interworking is standardized to ensure interoperability between different vendors and operators. Over releases, the definition has remained stable, indicating the maturity of the concept. However, with the advent of 5G and Wi-Fi 6, the interworking has evolved to include trusted and untrusted WLAN access, with different security and mobility mechanisms. The Home WLAN remains a key component of the operator's strategy to provide ubiquitous connectivity.

Purpose & Motivation

Home WLAN was created to allow mobile operators to leverage WLAN technology to extend their service coverage and capacity, particularly in indoor environments where cellular signals may be weak. Before its introduction, WLAN and cellular networks operated independently, and users could not seamlessly access operator services over WLAN. The 3GPP-WLAN interworking framework, including the Home WLAN concept, solves this by providing standardized mechanisms for authentication, authorization, and access to the mobile core network over WLAN. This enables operators to offer a unified service experience, offload data traffic, and reduce costs. It also allows users to benefit from higher bandwidth and better indoor coverage while maintaining a single subscription and consistent policies. The Home WLAN specifically addresses the need for a WLAN that is tightly integrated with the home operator's network, ensuring that the user's home subscription and services are available.