LTE-WLAN Interworking: 3GPP Release-12 Perspective


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LTE-WLAN Interworking: 3GPP Release-12 Perspective

  1. 1. LTE-WLAN Interworking: 3GPP Release-12 Perspective Nadeem Akhtar Centre of Excellence in Wireless Technology, Chennai IEEE Standards Workshop on Last Mile Connectivity 31 July 2013, Bangalore, India
  2. 2. Long Term Evolution (LTE) 31/07/2013 2 LTE Rel. 8/9 LTE-A Rel. 10/11 Beyond LTE-A Rel. 12/13
  3. 3. Technology Challenges 31/07/2013 3 • Billions of devices • Very large number of concurrent, active connections Scalability • Rapid growth in number of data subscribers and data usage • New communication paradigms and applications Capacity • Wide range of deployment scenarios with diverse traffic patterns Flexibility
  4. 4. Rel. 12 Focus Areas 31/07/2013 4 System Capacity Enhanced MIMO, New Carrier Type, Advanced Receiver HetNets and Small Cells User Plane Congestion, Core Network Overload WiFi Integration Network Selection Mobility Optimized Offloading New Business Opportunities Public Safety and Critical Communications Proximity Services Machine Type Communications
  5. 5. 3GPP-WiFi Interworking  Despite the increase in system capacity via technological enhancements , cellular networks are becoming more and more congested with increased data usage  In parallel, there is explosive growth in WiFi-enabled devices such as smartphones and tablets  Mobile operators see WiFi offload as the key towards relieving congestion in 3G/4G networks  Study Item on 3GPP-WLAN interworking introduced to find potential enhancements for tighter integration 31/07/2013 5
  6. 6. Cellular Data and Voice Growth Source: Ericsson Mobility Report, June 2013 31/07/2013 6
  7. 7. WiFi Data Usage Source: Informa Telecoms & Media, June 2013 Android devices only 31/07/2013 7
  8. 8. 3GPP-WiFi Interworking in Rel. 12  Earlier releases of 3GPP support interworking with WiFi in the Core Network (CN)  The current study focuses on Radio Access Network (RAN) level integration between LTE and operator-deployed WiFi networks  The enhancements are expected to enable ◊ Coordinated radio resource management ◊ Improved user Quality of Experience (QoE) ◊ Reduced battery power consumption 31/07/2013 8
  9. 9. Requirements  Provide improved two-directional load balancing  Improve WLAN utilization when it is available and not congested  Reduce or maintain battery consumption in the user device  Compatible with all existing CN WLAN-related functionality  Backward compatible with existing 3GPP/WLAN specifications  Rely on existing WLAN functionality and avoid changes to IEEE and WiFi Alliance specifications 31/07/2013 9
  10. 10. Deployment Scenario  WLAN deployed and controlled by operators and their partners  Several WLAN access points may be deployed within the coverage of a single 3G/4G cell  3G/4G base station may know the location and/or other WLAN access point parameters ◊ Scenarios where such information is unavailable are not excluded  No RAN level information exchange between 3G/4G RAN nodes and WiFi networks via standardized interface ◊ OAM-based information exchange possible 31/07/2013 10
  11. 11. Use Cases User moving towards WiFi coverage User moving out of WiFi coverage 31/07/2013 11 Data flow
  12. 12. Use Cases Some/all flows moved to from WiFi to 3GPP Some/all flows moved to from 3GPP to WiFi 31/07/2013 12
  13. 13. Technical Challenges Discovery and Scanning Access Selection Traffic Steering 31/07/2013 13
  14. 14. Access Selection and Traffic Steering  The proposed solutions have to address the following issues ◊ Operator deployed WLAN networks are often under-utilized ◊ User experience is suboptimal when UE connects to a overloaded WLAN ◊ Unnecessary WLAN scanning may drain UE battery resources  Two approaches are proposed ◊ Network provides UE with additional information to assist in deciding if/when to connect to available WLAN ◊ UE provides network with information about WLAN and the network decides if/when UE should connect to available WLAN 31/07/2013 14
  15. 15. Solution 1  RAN provides assistance information to the UE via broadcast signaling (and optionally dedicated signaling)  UE decides to steer traffic to WLAN or to 3GPP RAN based on ◊ RAN assistance information ◊ UE measurements ◊ Information provided by WLAN ◊ Policies obtained via the ANDSF or via existing OMA-DM mechanisms or pre-configured at the UE 31/07/2013 15
  16. 16. Solution 2  RAN provides assistance information to the UE through dedicated and/or broadcast signaling  UE decides to steer traffic to WLAN or to RAN based on ◊ RAN assistance information ◊ Rules specified in the RAN specification ◊ UE measurements ◊ Information provided by WLAN 31/07/2013 16
  17. 17. Solution 3  Network controls traffic steering for UEs via dedicated traffic commands ◊ May also take into account WLAN measurements reported by the UE  The traffic steering commands can override ANDSF policy for specific flows indicated in the command ◊ All other traffic continues to be subject to the ANDSF policy as applicable 31/07/2013 17
  18. 18. RAN Assistance Information • WLAN RSSI, WLAN BSS load and WLAN WAN metric • UMTS/LTE load, RSRP/RSCP WLAN and RAN Thresholds • Direct/indirect indication of RAN load Load Information • Maximum resource allocation the UE may receive in RAN Resource Allocation • Identifier(s) of the traffic flow(s) to be steered Traffic Information 31/07/2013 18
  19. 19. Current Status of Study  Qualitative comparison of the solutions is in progress in RAN WG2, based on ◊ Implementation complexity ◊ Specification impact ◊ Signaling overhead  This will lead to further narrowing down of options, which will then be evaluated quantitatively  Upon the completion of study, a decision will taken if changes to specifications are to be made  See 3GPP Technical Report TR 37.834 for more details 31/07/2013 19
  20. 20. Thanks!