Description
The Packet Switched Streaming Service (PSS) is a comprehensive 3GPP service framework designed for the streaming of multimedia content, such as audio and video, over IP-based packet-switched mobile networks. It was first introduced in 3GPP Release 99 and has evolved through subsequent releases to support new codecs, transport protocols, and network capabilities. PSS specifies an end-to-end architecture involving a streaming server and a client (the User Equipment, or UE). The service encompasses protocols for session establishment and control (like RTSP - Real Time Streaming Protocol), media transport (typically RTP over UDP), and media codec formats. It also includes mechanisms for bandwidth adaptation, buffering management, and quality of service (QoS) signaling to handle the variable conditions of wireless links.
At its core, PSS defines profiles and codecs to ensure interoperability between servers and clients from different vendors. Key media codecs historically include AMR-NB/WB for audio and H.263, MPEG-4 Visual for video, with later additions like H.264/AVC and HEVC. The transport layer is built on the IETF's RTP/RTCP for media delivery and control, while session control is handled via RTSP, SIP, or HTTP. The architecture also includes a presentation description, often provided via SDP (Session Description Protocol), which informs the client about the media streams available, their codecs, and network addresses.
PSS plays a critical role in the mobile service ecosystem by providing a standardized way to deliver real-time, on-demand, and live streaming content. It integrates with the core network's QoS mechanisms, allowing the network to allocate appropriate bearers for the streaming traffic. The service specifications cover not only the protocol stacks but also client and server behavior, file formats for streaming (like 3GPP file format), and metrics for performance testing. This standardization was crucial for the early deployment of mobile TV, video-on-demand, and other streaming applications, creating a consistent user experience across different operators and devices.
Purpose & Motivation
PSS was created to enable the delivery of real-time multimedia streaming services over 2.5G and 3G packet-switched mobile networks, which were a significant evolution from circuit-switched voice services. Prior to PSS, there was no standardized method for streaming audio and video over GPRS or UMTS networks, leading to potential interoperability issues between content providers, network equipment, and handsets. The service aimed to leverage the 'always-on' capability and higher data rates of packet-switched networks to offer new revenue-generating services like mobile TV, video clips, and audio streaming.
The development of PSS addressed the technical challenges of streaming over wireless links, which are prone to bandwidth fluctuations, latency, and packet loss. By defining a complete protocol suite and codec profiles, it ensured that streaming servers and clients could communicate effectively, adapting to network conditions to maintain acceptable quality. It also provided a framework for content providers to create services that could be deployed globally, fostering the growth of the mobile media market. As networks evolved to HSPA and LTE, PSS specifications were updated to support higher efficiencies and new capabilities, maintaining its relevance as a foundational streaming service standard.
Classification
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (27 CRs across 5 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the PSS function was enhanced with new capabilities including support for Server and Network Assisted DASH (SAND) to improve streaming efficiency, the addition of a High Dynamic Range (HDR) TV video profile for improved video quality, and explicit support for Virtual Reality (VR) content delivery. These additions expanded the service's ability to provide richer multimedia experiences and more efficient use of transport resources, as outlined in the general service requirements.
In Release 16, the PSS function was updated to formally introduce 5G Media Streaming (5GMS) procedures, including specific architectures and interactions for unicast downlink streaming. It also added support for Virtual Reality (VR) metrics within PSS and removed legacy codec support by deprecating H.263 and MPEG-4 Visual. Furthermore, the release provided corrections and clarifications for session handling, QoE metrics reporting, and configuration updates during non-streaming periods.
- PSS VR Metric Support TS 26.234CR0229
- Missing XML Data Type for Attributes in MBMS USD TS 26.346CR0658
- Corrections to 5G Media Streaming TS 26.511CR0001
- Introduction of switched uplink operation TS 38.214CR0106
- Removing H.263 and MPEG-4 Visual from PSS TS 26.234CR0231
- TV Video Profiles and 5G Media Streaming TS 26.116CR0014
+ 5 more changes
In Release 17, the PSS function was extended to include new data collection and reporting capabilities specifically for 5G Media Streaming. Additionally, corrections were made to the uplink streaming call flow for a defined collaboration scenario to ensure proper interoperability between the server and other network elements.
In Release 18, enhancements to the Packet Switched Streaming Service (PSS) focused on uplink and downlink streaming workflows. Key new capabilities included support for cascaded uplink-downlink media streaming collaboration and dynamic policy invocation for uplink streaming. The release also introduced improvements for downlink streaming to media players with different manifests and refined the associated call flows.
- [5GMSA_Ph2] Uplink streaming: removing FLUS and updating the workflows TS 26.501CR0042
- [5GMSA_Ph2] Downlink Streaming to Media Players with Different Manifests TS 26.501CR0046
- [5GMS_Ph2] Cascaded uplink-downlink media streaming collaboration TS 26.501CR0078
- [5GMS_Ph2] Addition the dynamic policies invocation for uplink streaming TS 26.501CR0081
- [5GMS_Ph2] Improvements on the multiple manifest downlink streaming call flow TS 26.501CR0061
- [5GMS_Ph2] Uplink Streaming: editorial correction TS 26.501CR0063
In Release 19, the PSS function introduced new features for Advanced Media Delivery in 5G Media Streaming, including an in-session unicast repair mechanism for MBMS object distribution to improve reliability. The release also brought improved time synchronization for MBMS and provided clarifications for supporting enhanced Quality of Service (QoS) specifically for media streaming services.
- [AMD_PRO-MED] In-session Unicast Repair for MBMS Object Distribution TS 26.346CR0677
- [FS_AMD] Advanced Media Delivery Features for 5G Media Streaming TS 26.804CR0024
- Improved Time Synchronization for MBMS TS 26.346CR0672
- Clarification on support of Improved QoS for media streaming services TS 26.501CR0109
Explore further
Broader topics and technologies where PSS plays a role.
Defining Specifications
3GPP specifications that define or reference PSS, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 22.233 vj00 | Packet-switched Streaming Service (PSS) Stage 1 | Rel-19 |
| TS 22.246 vj00 | MBMS User Services Specification | Rel-19 |
| TR 22.947 vj00 | Personal Broadcast Service (PBS) Use Cases | Rel-19 |
| TS 26.116 vj00 | TV Video Formats for 3GPP Services | Rel-19 |
| TS 26.140 vj00 | MMS Media Formats and Codecs Specification | Rel-19 |
| TS 26.141 vj00 | IMS Messaging & Presence Media Formats | Rel-19 |
| TS 26.142 vj00 | 3GPP TS 26.142: Dynamic and Interactive Multimedia Scenes (DIMS) | Rel-19 |
| TS 26.150 vj00 | Syndicated Feed Reception (SFR) Specification | Rel-19 |
| TS 26.233 vf00 | 3GPP Packet-Switched Streaming Service (PSS) | Rel-15 |
| TS 26.234 vj00 | 3GPP PSS Protocols and Codecs Specification | Rel-19 |
| TS 26.237 vj00 | IMS for PSS and MBMS Control | Rel-19 |
| TS 26.244 vj00 | 3GPP File Format (3GP) Specification | Rel-19 |
| TS 26.245 vj00 | 3GPP Timed Text Format Specification | Rel-19 |
| TS 26.246 vj00 | 3GPP SMIL Language Profile Specification | Rel-19 |
| TS 26.247 vj00 | 3GPP Progressive Download & DASH over HTTP | Rel-19 |
| TS 26.307 vj00 | 3GPP HTML5 Profile Specification | Rel-19 |
| TS 26.346 vj20 | MBMS User Services Media Codecs & Protocols | Rel-19 |
| TS 26.501 vj30 | 5G Media Streaming (5GMS) Architecture | Rel-19 |
| TS 26.511 vj00 | 5G Media Streaming Profiles, Codecs & Formats | Rel-19 |
| TS 26.804 vj10 | 5G Media Streaming Extensions Study | Rel-19 |
| TS 26.827 vc00 | IMS-based Streaming & Download Delivery Enhancements | Rel-12 |
| TS 26.849 vc10 | MBMS Operation on Demand (MooD) | Rel-12 |
| TS 26.851 vb20 | Enhancements to Multimedia (EMM) for PSS, MMS, MBMS | Rel-11 |
| TS 26.852 ve20 | MBMS user service profiles, APIs and transport enabler study | Rel-14 |
| TR 26.902 vj00 | Video Codec Performance for 3GPP Packet Services | Rel-19 |
| TR 26.903 vj00 | Video Capability Requirements for PSS and MBMS | Rel-19 |
| TR 26.905 vj00 | Study on Mobile 3D Video Services | Rel-19 |
| TR 26.906 vj00 | HEVC Evaluation for 3GPP Services | Rel-19 |
| TR 26.907 vj00 | HTML5 for 3GPP Services Study | Rel-19 |
| TR 26.909 vj00 | QoE Enhancement for Streaming Services | Rel-19 |
| TR 26.925 vj00 | Media Traffic Characteristics for 3GPP Networks | Rel-19 |
| TR 26.928 vj00 | Study on eXtended Reality (XR) in 5G | Rel-19 |
| TR 26.936 vj00 | Audio Codec Characterization Technical Report | Rel-19 |
| TR 26.937 vj00 | 3GPP PSS Characterization | Rel-19 |
| TR 26.938 vj00 | DASH Deployment Guidelines for 3GPP Networks | Rel-19 |
| TR 26.944 vj00 | QoE, ESQoS and SQoS metrics for 3G multimedia services | Rel-19 |
| TR 26.946 vj00 | MBMS User Services Overview | Rel-19 |
| TR 26.947 vj00 | FEC Evaluation for MBMS Enhancement | Rel-19 |
| TR 26.948 vj00 | Video enhancements for 3GPP Multimedia Services | Rel-19 |
| TR 26.949 vj00 | TV Service Profiles for 3GPP Networks | Rel-19 |
| TS 32.102 vj00 | Telecom Management Physical Architecture Framework | Rel-19 |
| TS 36.101 vj30 | LTE UE Radio Transmission & Reception Requirements | Rel-19 |
| TS 36.116 vj00 | E-UTRA Relay RF Requirements | Rel-19 |
| TS 36.117 vj00 | E-UTRA Relay RF Test Methods & Requirements | Rel-19 |
| TS 36.785 ve00 | LTE Sidelink V2V Services Study | Rel-14 |
| TS 36.786 ve00 | TR on V2X Services based on LTE sidelink | Rel-14 |
| TS 36.787 vf00 | V2X New Band Combinations for LTE | Rel-15 |
| TS 36.788 vf00 | V2X Phase 2 Technical Report for LTE | Rel-15 |
| TS 36.825 vd00 | Study on Additional LTE TDD Configurations | Rel-13 |
| TS 36.863 vc00 | CRS Interference Mitigation for Homogeneous Networks | Rel-12 |
| TS 36.877 vc00 | LTE Device to Device Proximity Services | Rel-12 |
| TS 36.878 vd00 | LTE Performance Enhancements for High Speed Scenarios | Rel-13 |
| TS 36.894 vd00 | Study on LTE Measurement Gap Enhancement | Rel-13 |
| TR 36.976 vj00 | LTE-based 5G Terrestrial Broadcast Overview | Rel-19 |
| TR 37.910 vj00 | 5G SRIT and NR RIT Self-Evaluation Report | Rel-19 |
| TS 38.133 vj20 | 5G UE Radio Requirements for RRC_IDLE Mobility | Rel-19 |
| TS 38.174 vj10 | NR Integrated Access and Backhaul Radio Spec | Rel-19 |
| TS 38.176 vj20 | IAB Conformance Testing Specification | Rel-19 |
| TS 38.211 vj10 | NR Physical Channels and Modulation | Rel-19 |
| TS 38.213 vj10 | NR Physical Layer Control Procedures | Rel-19 |
| TS 38.214 vj10 | NR Physical Layer Procedures for Data | Rel-19 |
| TS 38.300 vj00 | NG-RAN Overall Description | Rel-19 |
| TS 38.523 vj20 | 5G NR UE Conformance Testing: Idle/Inactive | Rel-19 |
| TS 38.811 vf40 | Study on NR Support for Non-Terrestrial Networks | Rel-15 |
| TR 38.833 vh00 | NR Demodulation Performance Enhancement | Rel-17 |
| TR 38.864 vi10 | Technical Report on Network Energy Savings for NR | Rel-18 |
| TR 38.878 vi40 | Technical Report on Advanced Receiver for MU-MIMO | Rel-18 |
| TS 45.820 vd10 | CIoT for Internet of Things | Rel-13 |