Demonstrating the Benefits of Self-Organising Networks

Transcription

1 Demonstrating the Benefits of Self-Organising Networks 3G, HSPA+, LTE Optimisation 10-11th March 2010 Neil Scully (Vodafone Group R&D, UK) Ljupco Jorguseski (TNO ICT, The Netherlands)

2 Outline 1. SON Introduction 2. SON activities in 3GPP and NGMN 3. Demonstrating SON benefits a) Handover optimisation SON algorithm (SOCRATES) b) Cell outage compensation SON algorithm (SOCRATES) c) Energy saving SON algorithm (TNO) 4. Summary and Recommendations 2/17

3 Building effective SON SON for LTE: Is it a reality? SON: Self-organising networks Self-configuration Self-optimisation Self-healing Focus on LTE Research and development + Significant efforts Advanced SON is complicated Standardisation + Some use cases standardised Slow progress Aligning SON with operator processes + Use cases represent operational tasks Alignment with practical aspects Building operator trust + Addressed by vendors Operators still need convincing > What is still missing? Real-life tests and trials Advanced optimisation functionality Integration with operator processes 3/17 Vodafone Group R&D

4 SON: What are the benefits? Reduction of manual effort OPEX Increase or decrease? CAPEX Efficiency More efficient use of engineers Capacity More efficient network Network quality Better optimisation Availability Reacting to failures Energy savings Switch-off unused BS > Focus is often on OPEX benefits, but other benefits are important as well > Benefits will increase as more SON functionality becomes available 4/17 Vodafone Group R&D

5 SON in 3GPP standards > Achieving operator benefit through multi-vendor standardisation Base stations from different vendors SON functionality from different vendor than base station vendor Implies centralised solution > NGMN (Next Generation Mobile Networks Alliance, has been the driving force behind SON for LTE Self-configuration Self-optimisation Rel. 8 Rel. 9 Rel ANR Self-configuration 2011 Load balancing Mobility robustness optimisation RACH optimisation Coverage and capacity optimisation Minimisation of drive tests Energy savings 5/17 Vodafone Group R&D

6 What is being standardised? (only interfaces relevant for SON are shown) Standardisation of Performance Mgmt and Configuration Mgmt Network Manager Itf-N Element Manager Control and monitoring Itf-S enodeb X2 enodeb UE measurements: - ANR (Rel. 8) - RACH optimisation (Rel. 9) - Minimisation of drive tests (Rel. 10) UE LTE-Uu Focus for distributed solutions: - Mobility robustness opt. (Rel. 9) - Load balancing (Rel. 9) 6/17 Vodafone Group R&D

7 Demonstrating SON benefits Concepts and ideas for SON are useful However, what will SON really do? Three example SON algorithms: Handover optimisation SON algorithm (SOCRATES) Cell outage compensation SON algorithm (SOCRATES) Energy saving SON algorithm (TNO) SOCRATES See 7/17

8 Handover optimisation: Introduction (Thomas Jansen, TU Braunschweig) Problem Non-optimal handover performance Objective Handover failures Ping-pong handovers Call dropping Automatic optimisation of the handover performance Approach Analyse the system behaviour Develop handover optimisation algorithm Control parameters Hysteresis Time-to-Trigger HO Drop X time Ping-pong 8/17

9 Handover optimisation: Analysis of system behaviour Call drops Call dropping ratio Time-to-Trigger [s] Hysteresis [db] 8 10 The above figure is based on using the same parameter settings for all cells The developed optimisation algorithm tunes cells individually 9/17

10 Handover optimisation: Demonstration of results WITHOUT SON WITH SON Handover Performance for the operating point (4, 0.48) Handover failure Ping-Pong handover Call dropping Handover performance (Optimisation) Handover failure Ping-Pong handover Call dropping 15 5 Ratio [%] 10 Ratio [%] Time [s] Time [s] Performance is improved by the optimisation algorithm, relative to static parameter settings 10/17

11 Cell Outage Compensation: Introduction Goal: Mitigate coverage hole resulting from the cell(s) in outage. SON approach: Automatic adjustment of control parameters at neighbor cells DL control parameters: Tx Power, Antenna Tilt UL control parameters: P o (open loop power control operating point), Antenna Tilt IMPORTANT: Measurements 1) Trade off between coverage improvement and quality degradation 2) UL control parameters have much higher impact (from sensitivity studies) so focus on target Rx Power (P o ), Antenna Tilt 11/17

12 Cell Outage Compensation: Demonstration of results (Mehdi Amirijoo, Ericsson) Compensating cell (blue) Compensated coverage hole (grey) 10th-perc DL throughput [Mbps] (averaged over compensating cells) 10th-perc UL throughput [Mbps] (averaged over compensating cells) Cell in outage (red) Control Parameter P 0 Increase in number of served UEs (relative to no compensation) 12/17

13 Energy Saving: Introduction 1600 DAILY TRAFFIC LOAD VARIATIONS NETWORK-WIDE TRAFFIC LOAD HOUR OF DAY 12 active sites 48 active sites For more details see TR (via 13/17

14 Energy Saving: Presentation of results 0.2 ENERGY CONSUMPTION (48,4) configuration Energy-optimised configuration (36,1) (12,1) (12,1) (12,1) (12,1) (12,1) (12,1) (12,1) (36,2) (48,2) (48,3) (48,4) (48,4) (48,3) (48,3) (48,4) (48,4) (48,4) (48,4) (48,3) (48,3) (48,2) (36,2) (36,1) Energy saving gain (sites, # carriers) for optimized energy consumption HOUR OF DAY Energy gain (upper bound) between 18% and 35% depending on quality target and assumptions for minimum power consumptions 14/17

15 Summary and recommendations Self-Organising Network (SON) benefits for handover: Proposed SON algorithm optimizes handover performance and sets handover operating points per cell The overall network performance is increased and the handover failure ratio and ping-pong ratio drop to zero in the shown case Self-Organising Network (SON) benefits for cell outage compensation: Proposed SON algorithm increases coverage (number of served UEs) at a cost of quality reduction (e.g. lower UL and DL throughputs) in the presented scenario Self-Organising Network (SON) benefits for energy saving: Considerable energy saving gains (up to 18% or 35%) can be achieved in areas with redundant capacity in off-peak traffic hours as shown in the example scenario Recommendations Investigate corresponding OPEX savings if SON algorithm is deployed for handover performance Clearly define acceptable quality degradation in order to deploy SON algorithm for cell outage compensation Deploy energy saving SON algorithm (direct OPEX gain in lower energy costs) 15/17

16 Questions 16/17

17 Contact Details Neil Scully (Vodafone) Ljupco Jorguseski (TNO) Mehdi Amirijoo (Ericsson) Thomas Jansen (TU Braunschweig) 17/17