Preferred Service Providers List

Description

The Preferred Service Providers List (PSPL) is a management object defined in 3GPP specifications that contains an ordered list of service provider identifiers. It is used by a User Equipment (UE) to guide its network selection and connection procedures, especially when accessing networks via non-3GPP access technologies such as Wireless Local Area Network (WLAN). The PSPL is typically provisioned on the Universal Integrated Circuit Card (UICC) by the mobile network operator (MNO) but can also be configured in the device's memory via device management protocols like OMA DM.

The primary operational role of the PSPL comes into play during Access Network Discovery and Selection Function (ANDSF) operations or more generic network selection logic. ANDSF is a core network function that provides the UE with policies to discover and select between 3GPP and non-3GPP access networks. The PSPL acts as a key input to these policies. When a UE scans for available WLAN networks, it can compare the discovered Service Set Identifiers (SSIDs) or other identifiers against the entries in its PSPL. The list is ordered by priority. The UE will attempt to connect to the highest-priority available service provider on the list, facilitating seamless attachment to partner or preferred hotspots.

The list entries are defined using the format of a Service Provider Identifier (SPID). The management of the PSPL—its creation, update, and deletion—is handled through standardized interfaces and protocols. For UICC-based storage, it is part of the file system on the SIM. For device-based management, it can be pushed via OMA DM or potentially by the ANDSF server itself as part of a policy container. The use of PSPL enhances the user experience by automating the connection to trusted and potentially billable WLAN networks, supporting offloading strategies, and enabling operator-controlled connectivity in heterogeneous network environments.

Purpose & Motivation

The PSPL was introduced to address the growing complexity of network selection in heterogeneous wireless environments. As smartphones became ubiquitous, users gained access to multiple network types: cellular (3GPP) and Wi-Fi (non-3GPP). Manually selecting a Wi-Fi network from a long list was cumbersome for users and inefficient for operators wishing to steer traffic to preferred or partnered networks. The PSPL provides an automated, operator-controlled mechanism to prioritize network selection.

Its creation was motivated by the need to support seamless mobility and traffic offloading. For operators, offloading data traffic to WLAN is a valuable capacity management tool. The PSPL allows an operator to ensure that a subscriber's device automatically connects to the operator's own branded Wi-Fi hotspots or to a partner's network, rather than an unknown or less-preferred public Wi-Fi. This improves security (by steering towards trusted networks), enables seamless authentication (via SIM-based credentials like EAP-AKA), and supports business models like bundled cellular-Wi-Fi services. It solved the limitation of purely signal-strength-based selection, introducing a policy-driven, operator-centric priority scheme into the device's connection logic.