Small Cell Deployments: Impacts on theEnergy EfficiencyRouzbeh Razavi
Traffic growth for communication networks                       3                  10                       2             ...
How can weaddress theseproblems?  COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
Historic Capacity Gains in WirelessNetworks    Wireless Network Capacity    Gains 1950-2000    15x by using more spectrum ...
Small Cells - A Necessary Topology Evolutionfor Future Data GrowthMoving to hierarchical cell structures with small cells ...
How canSmall CellsimproveEnergyEfficiency? COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
Impact of femtocells on the network energyconsumption• Telecommunications is a large consumer of  energy (e.g. Telecom Ita...
Methodology & ModelGiven the traffic demand map for an area, find out the optimalnetwork topology in terms of the number a...
Energy Consumption Improvements                                                                                           ...
Reducing energy consumptionIdle mode procedures for Small Cells When femtocells become more widely deployed, their energy ...
Challenges and Ongoing ResearchEnabling idle mode for small cells requires    - Efficient algorithms to enable sleeping/ a...
What is thefuture forMacrocells? COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
lightRadio Cube and Active Antenna Array    lightRadio       cube                                                         ...
What Do We Mean By lightRadio AAA?Part I: “Invisible infrastructure” co-locating the         RF with the antenna          ...
What Do We Mean By lightRadio AAA?Part II: Places a “lightRadio cube” transceiver behind         each antenna element    R...
Remarks & Conclusions• Wireless data traffic is increasing significantly in the future.    – Energy consumption of network...
COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
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Small Cell Deployments: Impacts on the Energy Efficiency

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Small Cell Deployments: Impacts on the Energy Efficiency

  1. 1. Small Cell Deployments: Impacts on theEnergy EfficiencyRouzbeh Razavi
  2. 2. Traffic growth for communication networks 3 10 2 10 Traffic (Tb/s) 1 10 Wireless data 0 10 P2P grows fastest -1 Wireless Voice 10 -2 10 2010 2015 2020 Year Data from: RHK, McKinsey-JPMorgan, AT&T, MINTS, Arbor, ALU, and Bell Labs Analysis: Linear regression on log(traffic growth rate) versus log(time) with Bayesian learning to compute uncertainity. Transition to LTE will increase capacity trough more spectrum, better scheduling, and MIMO, but these gains are not sufficient. Energy consumption of networks will become an increasing problem. “More of the same” will not be good enough. COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
  3. 3. How can weaddress theseproblems? COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
  4. 4. Historic Capacity Gains in WirelessNetworks Wireless Network Capacity Gains 1950-2000 15x by using more spectrum (3 GHz vs 150 Mhz) 5x from better voice coding 5x from better MAC and modulation methods 2700x from smaller cells Total gain 1 million fold Source: William Webb, Ofcom. COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
  5. 5. Small Cells - A Necessary Topology Evolutionfor Future Data GrowthMoving to hierarchical cell structures with small cells can: • Significantly increase the capacity in the same bandwidth • Significantly reduce the energy consumption of networks COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
  6. 6. How canSmall CellsimproveEnergyEfficiency? COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
  7. 7. Impact of femtocells on the network energyconsumption• Telecommunications is a large consumer of energy (e.g. Telecom Italia uses 1% of Italy’s total energy consumption, NTT uses 0.7% of Japan’s total energy consumption)Opportunity: Small cells have the potential to reduce the transmit power required for serving a user by a factor in the order of 103 compared to macrocells. Small cells can provide significant capacity improvement in hotzone areas where traffic demand is high and hence can replace traditional cumbersome macrocells Due to their reduced coverage, small cells normally serves fewer users and hence enable significant reduction of power consumption if efficient idle mode procedures are enabled Source: BBC News - How the world is changing COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
  8. 8. Methodology & ModelGiven the traffic demand map for an area, find out the optimalnetwork topology in terms of the number and the transmitpower of macrocell and small cell requiredConsider variations of hourly traffic demand to enableinvestigation of idle mode proceduresSystem Model: PNo_Load PTotal PNoLoad PTotal Macrocellγ= α= PTotal PTotal Smallcell Typical Values : PTotal Macro = 1350 [W ] PTotal Smallcell = 14 . 7 [W ] γ Macro = 0 . 55 , γ Macro = 0 . 60 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
  9. 9. Energy Consumption Improvements Factor of 45.7 Energy 4 ReductionObservations 10 x 10 Macrocells Only 9 PIF Macrocells=15%, PIF Smallcells=15%, γm =0.4, γs =0.4Significant power reduction gains as the traffic PIF Macrocells=30%, PIF Smallcells=30%, γm =0.2, γs =0.3demand increases (Small Cells can replace 8 PIF Macrocells=50%, PIF Smallcells=50%, γm =0.2, γs =0.05macrocells) 7 Total Power [W] 6Improving the idle mode energy efficiency ofsmall cells (γs) is significantly rewarding 5 4Challenge 3 2Maintaining high Quality of Service (QoS) whileenabling efficient idle mode procedures for 1small cells 0 2010 2011 2012 2013 2014 2015 2016 Year References: [1] R. Razavi and H. Claussen, “Urban Small Cell Deployments: Impact on the Network Energy Consumption" in Proc. IEEE Wireless Communications and Networking Conference (WCNC),Paris, France, Apr. 2012. COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
  10. 10. Reducing energy consumptionIdle mode procedures for Small Cells When femtocells become more widely deployed, their energy consumption becomes a concern. Idle mode procedures can: • Significantly reduce energy consumption • Reduce power density in the home • Reduce mobility procedures and associated signalling • Reduce interference caused by pilot transmissions Femtocell activation based on noise rise from active UE allows to activate the femto only for serving a callReferences:[1] I. Ashraf, L. T. W. Ho, and H. Claussen, “Improving energy efficiency of femtocell base stations via user activity detection," in Proc. IEEE Wireless Communications and Networking Conference (WCNC), Sydney, Australia, Apr. 2010.[2] H. Claussen, I. Ashraf, and L. T. W. Ho, “Dynamic idle mode procedures for femtocells," Bell Labs Technical Journal, to be published in 2010. COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
  11. 11. Challenges and Ongoing ResearchEnabling idle mode for small cells requires - Efficient algorithms to enable sleeping/ awaking - Modular hardware design that allow independent operation of components - Hardware design that fulfil the time to reconfigure requirements after awaking - Self-configuration/Optimisation algorithms that can swiftly adapt to the environment changes after awaking Femtocell energy consumption - Today Femtocell energy consumption – Optimized design COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
  12. 12. What is thefuture forMacrocells? COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
  13. 13. lightRadio Cube and Active Antenna Array lightRadio cube Digital link Active Antenna Array COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
  14. 14. What Do We Mean By lightRadio AAA?Part I: “Invisible infrastructure” co-locating the RF with the antenna X X ⌧ X X ⌧Conventional X Distributed X Active ⌧ X X ⌧Node B site X Node B site X Antenna ⌧ X X ⌧ X X ⌧ RF AAA Node B site Remote Radio Head Move RF to Integration antenna CPRI CPRI OR Cloud Reduces Energy consumption by ~50% COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
  15. 15. What Do We Mean By lightRadio AAA?Part II: Places a “lightRadio cube” transceiver behind each antenna element RF •Pico Cell •Micro Cell (SNAP) •Macrocell upgradeEthernet or CPRI Innovative Designs can result significant additional reductions of energy consumption for macrocells COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
  16. 16. Remarks & Conclusions• Wireless data traffic is increasing significantly in the future. – Energy consumption of networks becomes a major problem.• Small cells are a necessary topology evolution for future data growth and for reducing energy consumption. – Compared to an architecture consisting of only macrocells a hybrid deployment results in significant energy reduction gains – Idle mode procedures in combination with a modular hardware design are essential. – Future research focuses on modular hardware and software design of small cells that that can enable efficient idle mode procedures• Light Radio can improve energy efficiency of base-stations. – Removing cable losses by integrating RF part and antenna into the “lightRadio Cube” reduces energy consumption by ~50%. – Individual control of antenna elements enables large scale antenna systems which can significantly reduce the energy consumption for macrocells. COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
  17. 17. COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

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