Radio Local Area Network

Description

A Radio Local Area Network (RLAN) is a type of wireless network that provides connectivity over a limited geographic area, typically using unlicensed spectrum bands like 2.4 GHz or 5 GHz. Common examples include Wi-Fi based on IEEE 802.11 standards. In 3GPP, RLAN integration involves mechanisms for interworking between cellular networks (e.g., 3G, 4G, 5G) and RLANs to enable seamless service delivery. The architecture includes components such as the Access Point (AP) for RLAN access, user equipment (UE) with dual connectivity capabilities, and network functions like the Access Network Discovery and Selection Function (ANDSF) or 5G Core elements for policy control. RLAN interworking works through protocols that allow authentication, authorization, and traffic steering between cellular and RLAN domains. For instance, in 5G, non-3GPP access integration uses N3IWF or TNGF to connect RLANs to the core network, supporting secure tunneling and session management. Key aspects include mobility management, where UEs can hand over sessions between RLAN and cellular without interruption, and quality of service (QoS) mapping to ensure consistent performance. RLANs play a role in offloading data traffic from congested cellular networks, enhancing capacity in hotspots like stadiums or airports. 3GPP specifications define interfaces and procedures for trusted and untrusted RLAN access, with enhancements in later releases for tighter integration with NR and network slicing.

Purpose & Motivation

RLAN integration in 3GPP was introduced to leverage the widespread deployment of Wi-Fi and other unlicensed wireless technologies to complement cellular networks. As mobile data demand surged, cellular networks faced congestion, especially in indoor and dense urban areas, where RLANs offer cost-effective capacity expansion. The purpose is to enable seamless, secure, and efficient interworking, allowing users to experience continuous connectivity and improved data rates. Historically, early cellular and Wi-Fi networks operated independently, leading to fragmented user experiences and manual switching. 3GPP addressed this by standardizing interworking procedures, starting with basic offloading in earlier releases and evolving to deep integration with 5G core. This solves problems like network overload, coverage gaps, and inconsistent QoS, motivated by the need for converged access in the era of heterogeneous networks. By integrating RLANs, 3GPP supports enhanced mobile broadband and supports diverse use cases, from residential broadband to enterprise solutions, driving towards unified connectivity frameworks.