Description
WLAN Selection Policy (WLANSP) is a core component of the Access Network Discovery and Selection Function (ANDSF) management object. It is a structured XML-based policy that provides the User Equipment with deterministic criteria for when and how to connect to available WLAN networks. The policy is dynamically provisioned by the operator's ANDSF server to the UE over an S14 reference point. The UE's ANDSF client then interprets and enforces these rules, automating the network selection process which would otherwise be manual or based on simplistic signal strength.
The policy contains several key elements. It includes discovery information, which lists available WLAN access networks and their properties (SSIDs, roaming partners). More critically, it contains selection rules. These are prioritized "if-then" statements where the conditions (e.g., current cellular signal strength, WLAN signal quality, time of day, location, UE velocity) are evaluated against thresholds. If the conditions are met, the rule's action is executed, such as connecting to a specific WLAN, steering specific IP flows to WLAN, or forbidding a connection. The policies can be hierarchical, with global rules and more specific exceptions, and can be updated by the network based on changing conditions like congestion.
WLANSP works in conjunction with other ANDSF policies like Inter-System Routing Policies (ISRP) and Inter-System Mobility Policies (ISMP). While ISRP/ISMP govern traffic routing between 3GPP and WLAN for active connections, WLANSP specifically manages the initial selection and connection to the WLAN radio access point itself. Its enforcement is a continuous background process; the UE periodically re-evaluates the policy conditions to determine if a more preferred WLAN has become available or if the current connection should be released. This mechanism is crucial for implementing operator-controlled Wi-Fi offloading strategies and ensuring a high-quality, seamless user experience across heterogeneous networks.
Purpose & Motivation
WLANSP was created to solve the problem of inefficient and user-driven WLAN selection, which often led to poor network performance and underutilization of Wi-Fi resources. Before ANDSF and WLANSP, UEs typically connected to WLANs based solely on stored SSID preferences and received signal strength, with no awareness of the core network's load, the backhaul quality of the WLAN, or the user's service requirements. This resulted in users connecting to congested or poor-quality Wi-Fi networks even when a strong cellular signal was available, degrading the overall experience.
The motivation was to give mobile operators intelligent control over the UE's access selection behavior in a multi-access environment. By deploying WLANSP, operators could proactively manage traffic distribution between their cellular (3GPP) and Wi-Fi (non-3GPP) assets. For example, an operator could define a policy to offload delay-tolerant traffic to WLAN when the cellular cell is congested, or to connect to a carrier-grade Wi-Fi hotspot when the UE is stationary and indoors to provide higher throughput and conserve cellular spectrum.
WLANSP, introduced as part of the broader ANDSF framework in Release 8 and enhanced in later releases, represented a shift from network-centric to user-equipment-centric policy enforcement. It empowered the UE to make smart, real-time decisions based on a rich set of operator-provided parameters, moving beyond simple offload to enable truly optimized multi-access connectivity. This was a foundational concept for later traffic steering and network selection mechanisms in 4G and 5G.
Classification
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (213 CRs across 6 releases). Complements the general historical overview above with the evidence-based evolution of this function.
Studied in Rel-12, normative work from Rel-15.
In Release 15, the WLAN Selection Policy (WLANSP) function was newly introduced as a component of UE policy information, structured within a Policy Section that can contain one or multiple WLANSP rules. This introduction was part of a broader enhancement of UE policy management, which included clarifications on UE policy configuration, delivery, and initial provisioning. The release also defined that a Policy Section could combine WLANSP rules with non-3GPP access network selection information for integrated access selection guidance.
- Additional PDU Session Type in Route Selection Descriptor TS 23.503CR0019
- Clarification on usage of ePDG selection procedures TS 24.302CR0662
- Coding of WLAN selection criteria entry TS 24.526CR0005
- Addition of Reflective QoS Timer in PDU session related policy information TS 23.503CR0005
- UE policies granularity and UE assistance for policy evaluation TS 23.503CR0011
- Update of UDR policy related subscription TS 23.503CR0021
+ 39 more changes
In Release 16, the WLAN Selection Policy (WLANSP) was enhanced to integrate with trusted non-3GPP access networks, as indicated by the CR title "Update to WLAN selection procedure because of trusted non-3GPP access". This included defining procedures for TNAN and PLMN selection using a trusted WLAN, and the WLANSP rules were formally structured as part of a Policy Section, which could contain a combination of WLANSP rule(s) and non-3GPP access network selection information.
- Support for Multi-Access PDU Session in URSP and PDU session selection TS 23.503CR0208
- Access and mobility related policy information for 5G-RG TS 23.503CR0236
- 23.503 part of PCF selection for PDU sessions with same DNN and S-NSSAI TS 23.503CR0265
- Update to Policy Framework for TSC TS 23.503CR0310
- Update to WLAN selection procedure because of trusted non-3GPP access TS 24.502CR0075
- TNAN and PLMN selection procedures using trusted WLAN TS 24.502CR0084
+ 41 more changes
In Release 17, the WLANSP (WLAN Selection Policy) function was enhanced as part of the broader UE policy information, which is managed within a Policy Section that can contain one or multiple WLANSP rules. The release specifically extended UE policy control to support new services, including ProSe (Proximity Services) based services and ProSe U2N (User-to-Network) relay, as indicated in the CR titles for UE policies for 5G ProSe and extending UE policy control for ProSe.
- BSF enhancement on PCF Discovery for dynamic AM policy TS 23.503CR0506
- Access and mobility policy control functionality to enable dynamic change of AM Policies TS 23.503CR0520
- Policy control based on satellite backhaul information TS 23.503CR0539
- ProSe Policy TS 23.503CR0533
- Policy control of data rate per network slice TS 23.503CR0552
- Policy control enhancement for local notification TS 23.503CR0587
+ 25 more changes
In Release 18, the WLAN Selection Policy (WLANSP) function was enhanced to support network slice-based selection for trusted non-3GPP access. Specifically, the ANDSP (Access Network Discovery and Selection Policy) was extended to enable TNGF (Trusted Non-3GPP Gateway Function) selection based on the S-NSSAI needed by the UE, aligning with similar enhancements made for N3IWF selection. These updates were part of broader policy control enhancements for multi-modal services and non-3GPP access network selection.
- N3IWF selection enhancement for support of S-NSSAI needed by UE TS 23.503CR0741
- NWDAF- assisted URSPs introduced in policy decision TS 23.503CR0769
- KI#4 23.503 PCC rule for common EAS, DNAI selection TS 23.503CR0776
- Policy control for dynamic satellite backhaul TS 23.503CR0788
- DN Performance Analytics usage in PDTQ policy TS 23.503CR0799
- Policy update to support policy control enhancements for multi-modal services TS 23.503CR0835
+ 65 more changes
In Release 19, the WLAN Selection Policy (WLANSP) function was enhanced to explicitly support rules provided by the Home PLMN (HPLMN), as indicated by the CR title "WLANSP and URSP rules provided by the HPLMN". Furthermore, corrections were made to the handling of manual and automatic mode WLAN selection procedures, ensuring alignment within the UE policy association framework. These updates refine the policy control framework for non-3GPP access network selection information, which includes WLANSP rules as part of a Policy Section.
- Minimize number of UE and AM Policy Associations TS 23.503CR1288
- Local Offloading Policy to support Local Handling of Edge Computing TS 23.503CR1348
- KI#1 Clarification on Local Offloading Policy TS 23.503CR1401
- PCF use of QoS and policy assistance information analytic TS 23.503CR1303
- Corrections to the handling of the UE and the AM Policy association TS 23.503CR1308
- Misalignment text in AM and UE policy association with respect to local configuration TS 23.503CR1309
+ 8 more changes
In Release 20, the WLAN Selection Policy (WLANSP) function was enhanced to integrate within a unified **Policy Section**, which can now contain a combination of WLANSP rule(s) and non-3GPP access network selection information. This release also introduced new policy control capabilities based on abnormal user plane traffic analytics and traffic pattern analytics. Furthermore, it added support for policy control related to network energy saving, including Background Data Transfer (BDT) and PDTQ, as part of the broader UE policy control framework.
- Policy control based on abnormal user plane traffic analytics and traffic pattern analytics TS 23.503CR1599
- Service Adjustment based on Exposure - Policy TS 23.503CR1600
- Adding BDT, PDTQ and UE policy control for network energy saving TS 23.503CR1612
- Policy control based on new Abnormal User Plane Traffic Analytics TS 23.503CR1613
- Correction on QoS and policy assistance analytics TS 23.503CR1627
Explore further
Broader topics and technologies where WLANSP plays a role.
Defining Specifications
3GPP specifications that define or reference WLANSP, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 23.503 vk00 | 5G Policy and Charging Control Framework | Rel-20 |
| TS 24.302 vj00 | Access to EPC via non-3GPP networks; Stage 3 | Rel-19 |
| TS 24.312 vj00 | ANDSF Management Objects Specification | Rel-19 |
| TS 24.502 vj20 | 5G Core Access via Non-3GPP Networks; Stage 3 | Rel-19 |
| TS 24.526 vj30 | UE Policies for 5GS; Stage 3 | Rel-19 |