BeFEMTO Winter School6-10 February 2012                        Interference Management in Co-                         Chan...
Outline• Femtocell Deployment Overview• 3GPP status on Interference Management• System-Level Simulation Framework• Evaluat...
Femtocell Deployment OverviewBeFEMTO Winter School |                SCET/URD1/Femtocell | Interference Management in Co-Ch...
Coexistence Scenario• Femtocells are small base stations usually deployed within the macrocell  network   • Mobile operato...
Worst-case• Co-channel deployment   • Same carrier• Downlink + Closed access   • Non authorised user in the vicinity of th...
3GPP status on Interference ManagementBeFEMTO Winter School |                SCET/URD1/Femtocell | Interference Management...
Architecture (Rel.10)                                                                                                     ...
Rel.8/9 - Inter-Cell Interference Coordination (ICIC) (1/2)• Frequency domain solution         • Data channel protection• ...
Rel.8/9 - Inter-Cell Interference Coordination (ICIC) (2/2)• Downlink interference management         • Relative Narrowban...
Rel.10 - enhanced ICIC (eICIC) (1/4)• Specifically targets Heterogeneous Networks (HetNet)   • Small Cells• Time domain so...
Rel.10 - enhanced ICIC (eICIC) (2/4)• Downlink power control   • Targets femtocell   • Power is adjusted based on surround...
Rel.10 - enhanced ICIC (eICIC) (3/4)• Almost Blank Subframe (ABS)    • During defined subframes, the Aggressor cell does n...
Rel.10 - enhanced ICIC (eICIC) (4/4)• Cell Range Extension (CRE)   • Through broadcasted information (handover/camp bias) ...
Rel.11 - ICIC still in discussion (1/2)• further enhanced ICIC (feICIC) for non-CA based deployment    • Some proposals un...
Rel.11 - ICIC still in discussion (2/2)• ICIC for CA based deployment    • For each Rel.10+ UE,                   • One Pr...
System-Level Simulation FrameworkBeFEMTO Winter School |                SCET/URD1/Femtocell | Interference Management in C...
System-Level Simulation (SLS)• SLS allows large scale network representation         • Several (macrocell) base stations  ...
Evaluation Methodology (3GPP/3GPP2/IEEE802.16m)• Monte-Carlo Approach                          Link                       ...
Macrocell Layout• 2D hexagonal layout, each site has 3 sectors (cells)   • 1 Central site   • 1st tier: 6 Sites   • 2nd ti...
Long Term Parameters (1/3)                                                                                                ...
Long Term Parameters (2/3)• Shadowing   • Random variable representing the obstacles between one cell and one point     in...
Long Term Parameters (3/3)• G-factor can be evaluated every where in the 2D plan without shadowing, without wrap-around   ...
Users’ Drop• Users are uniformly dropped over the 2D plan   • Attachment to the best macrocell drop: v=indoor, o=outdoor  ...
Femtocell Urban Model (1/2)• Dual-Stripes [3GPP TR.36.814]   • 2 stripes of 20 blocks, up to 6 floors   • Pathloss (dB, di...
Femtocell Urban Model (2/2)• 5x5 Grid [3GPP TR.36.814]   • 25 blocks   • Pathloss (dB, distance d in meter)               ...
Femtocell & Users’ Drop• Femtocell deployment   • Deployment probability inside a block                   • Random positio...
Link to System •           With fast fading, SINR is computed on each subcarriers •           One SINR is derived using co...
Evaluation of Power ControlBeFEMTO Winter School |                SCET/URD1/Femtocell | Interference Management in Co-Chan...
System simulation assumptions Parameter                                                              Value                ...
Static Evaluation - 5x5 Grid (1/2)• Independent CSG per femtocell                                                         ...
Static Evaluation - 5x5 Grid (2/2)• Outage   • One user is in outage if its G-factor is below -6dB• Independent CSG       ...
System simulation assumptions (2) Parameter                                                              Value            ...
Static Evaluation - Dual-Stripes• Independent CSG                                                          UE in outage (-...
Evaluation of Frequency Partitioning SchemesBeFEMTO Winter School |                SCET/URD1/Femtocell | Interference Mana...
Fractional Frequency Reuse (FFR)• Cell space is divided in two:         • Inner Region         • Outer Region (edge users)...
Soft Frequency Reuse (SFR)• Cell space is divided in two:         • Inner Region         • Outer Region (edge users)• Edge...
Resource Allocation in LTE Rel.8/9                                                                                        ...
Example of FFR/SFR in LTE Rel.8/9• FFR: 2 subbands per outer region• SFR : 2 subbands per outer regionBeFEMTO Winter Schoo...
Macrocell Only• Comparison between FFR, SFR and Reuse 1 (IFR)• FFR scheme improves significantly the SINR   • May be a goo...
System simulation assumptions Parameter                                                              Value                ...
Dynamic Evaluation - MIMO• Cell throughput                                                                      1         ...
Dynamic Evaluation - MIMO• Mobile throughput                                                                       1      ...
ConclusionsBeFEMTO Winter School |                SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell De...
Conclusions• Spectrum being a scarce resource, frequency reuse is of major interest• Under such co-channel deployment, int...
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Interference Management in Co-Channel Femtocell Deployment

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Transcript of "Interference Management in Co-Channel Femtocell Deployment"

  1. 1. BeFEMTO Winter School6-10 February 2012 Interference Management in Co- Channel Femtocell Deployment Massinissa Lalam 08-02-2012
  2. 2. Outline• Femtocell Deployment Overview• 3GPP status on Interference Management• System-Level Simulation Framework• Evaluation of Power Control• Evaluation of Frequency Partitioning Schemes• ConclusionsBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 2This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  3. 3. Femtocell Deployment OverviewBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 3This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  4. 4. Coexistence Scenario• Femtocells are small base stations usually deployed within the macrocell network • Mobile operator has “no control” over the deployment location MUE1 femtocell macro base station FUE MUE2• Femtocells have 3 access policies • Closed (only femto users can connect) • Open (all users) • Hybrid (all users + priority to femto users)BeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 4This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  5. 5. Worst-case• Co-channel deployment • Same carrier• Downlink + Closed access • Non authorised user in the vicinity of the femtocell may experience severe interference coming from the femtocell FUE2 femtocell1 MUE3 macro base station MUE1 MUE2 FUE1• Thus, the need of Interference Management solutionsBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 5This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  6. 6. 3GPP status on Interference ManagementBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 6This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  7. 7. Architecture (Rel.10) S1 S1 S1 S1 X2 X2 3GPP Rel.10BeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 7This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  8. 8. Rel.8/9 - Inter-Cell Interference Coordination (ICIC) (1/2)• Frequency domain solution • Data channel protection• Indicators exchange through X2 • macro / pico• Uplink interference management • Overload Indicator (OI) • eNB reports the level of interference received − Low, Medium, High • Reactive process • High Interference Indicator (HII) • eNB sends 1 bit per resource block (RB) − Indicate Cell-edge user on this resource − Informed neighbours will avoid these RB at cell-edge • Proactive processBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 8This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  9. 9. Rel.8/9 - Inter-Cell Interference Coordination (ICIC) (2/2)• Downlink interference management • Relative Narrowband Transmit Power (RNTP) Indicator • eNB advertises Tx power per RB • Proactive process • Enables (dynamic) frequency partitioning Hard Frequency Reuse Fractional Frequency Reuse (FFR) Soft-Frequency Reuse (SFR)BeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 9This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  10. 10. Rel.10 - enhanced ICIC (eICIC) (1/4)• Specifically targets Heterogeneous Networks (HetNet) • Small Cells• Time domain solution • Control channel protection• Information exchange through X2 • macro/pico or OAM configuration (TR-069) • macro/pico/femto• Focus only on Non-Carrier Aggregation (CA) scenariosBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 10This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  11. 11. Rel.10 - enhanced ICIC (eICIC) (2/4)• Downlink power control • Targets femtocell • Power is adjusted based on surrounding • Measurements performed by the femtocell − DL & UL • Need of one Network Listen Module (NLM) − Not specified − But always required by OperatorsBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 11This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  12. 12. Rel.10 - enhanced ICIC (eICIC) (3/4)• Almost Blank Subframe (ABS) • During defined subframes, the Aggressor cell does not transmit its (control + data) channels to protect a Victim cell • ABS pattern transmitted via X2 (dynamic) for macro/pico • Macro/Pico → Aggressor/Victim normal ABS F e m to F e m to or via OAM (semi-static) for macro/femto • Macro/Femto → Victim/Aggressor M a c ro M acroBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 12This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  13. 13. Rel.10 - enhanced ICIC (eICIC) (4/4)• Cell Range Extension (CRE) • Through broadcasted information (handover/camp bias) UEs stay connected to picocells (hotspot) • Bias leads to low SINR • Requires advanced UE receiver to cope with low SINR • Interference cancellationBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 13This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  14. 14. Rel.11 - ICIC still in discussion (1/2)• further enhanced ICIC (feICIC) for non-CA based deployment • Some proposals under discussion: • At the transmitter side in DL − Combination of ABS + power reduction • At the receiver side in DL − Use of advanced UE receiver (cancellation/discard of known signals such as CRS …)• ICIC for CA based deployment • In CA deployment, several cells/ component carriers (CCs) are aggregated • Up to 5 CCs (100MHz maximum bandwidth) • Cross scheduling among the CCs is possibleBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 14This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  15. 15. Rel.11 - ICIC still in discussion (2/2)• ICIC for CA based deployment • For each Rel.10+ UE, • One Primary Cell (PCell) is assigned among the pool of cells − Carrying control/data information • The rest of the cells are seen as Secondary Cells (SCells) − Carrying data • PCell/SCell selection is under discussion Macro UE A Macro UE B Pico UE • Control signaling on f 1 and/or f 2 • Control signaling on f 1 • Control signaling on f 2 • Data on f 1 and/or f 2 • Data on f 1 and/or f 2 • Data on f 1 and/or f 2 Pico Macro f1 f1 f2 f2BeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 15This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  16. 16. System-Level Simulation FrameworkBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 16This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  17. 17. System-Level Simulation (SLS)• SLS allows large scale network representation • Several (macrocell) base stations • Up to a hundred of users attached per base station• SLS aims at evaluating the system performance in this large-scale configuration • Radio resource management algorithms • Interference mitigations techniques • Coverage estimation …• Various statistics are gathered for this purpose • Throughput • Fairness • Outage • Cell activity • Realistic traffic statistics • Frame/Packet error rates • Frame/Packet acknowledgement time …BeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 17This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  18. 18. Evaluation Methodology (3GPP/3GPP2/IEEE802.16m)• Monte-Carlo Approach Link System Static Network construction Mobile deployment Computation of long-term parameters Physical Layer (pathloss, antenna gains, shadowing) Abstraction Dynamic Computation of short-term parameters Look-Up Table (fast-fading) SINR (BLER vs SINR) Scheduling, HARQ, … Throughput, Coverage, …BeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 18This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  19. 19. Macrocell Layout• 2D hexagonal layout, each site has 3 sectors (cells) • 1 Central site • 1st tier: 6 Sites • 2nd tier: 12 Sites Wrap-Around Copy of the main cluster to combat the edge effectBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 19This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  20. 20. Long Term Parameters (1/3) R P• Let P be a point in the 2D plan θ• Pathloss from a macrocell base station • @ 2GHz, R distance from a site in meters PL( R ) = 15.3 + 37.6 log10 R + [Wall attenuation ] in dB• Antenna gain • Cell   θ 2  •15   GBS (θ ) = G0 − min 12 θ   , Gf2b in dB •10 •Antenna gain (dB)   3dB     •5 • Point GUE = G1 = 0dB •0 •-5 •-10 •-150 •-100 •-50 •0 •50 •100 •150 •Direction (deg)BeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 20This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  21. 21. Long Term Parameters (2/3)• Shadowing • Random variable representing the obstacles between one cell and one point in the 2D plan • Correlation SF ~ N (0, σ SF ) in dB 2 • 1 between intra-site cells • 0.5 between inter-site cells• Power received by the point P from a base station (BS) in dB PRx ( BS ) = PTx ( BS ) + GBS (θ ) +GUE -PL( R )-SF• Signal to Interference-plus-Noise Ratio (Geometrical Factor) PRx ( BSserv ) G - factor = ∑ PRx ( BSitrf ) + Ptherm interferersBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 21This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  22. 22. Long Term Parameters (3/3)• G-factor can be evaluated every where in the 2D plan without shadowing, without wrap-around with shadowing, with wrap-aroundBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 22This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  23. 23. Users’ Drop• Users are uniformly dropped over the 2D plan • Attachment to the best macrocell drop: v=indoor, o=outdoor Run 0 - Mobile 3000 25 24 2000 46 45 26 43 42 28 27 47 7 6 44 22 21 1000 29 10 9 8 4 3 23 meters 49 48 11 1 0 5 40 39 0 50 13 12 2 19 18 41 31 30 14 16 15 20 37 36 -1000 32 52 51 17 55 54 38 53 34 33 56 -2000 35 -3000 -3000 -2000 -1000 0 1000 2000 3000 metersBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 23This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  24. 24. Femtocell Urban Model (1/2)• Dual-Stripes [3GPP TR.36.814] • 2 stripes of 20 blocks, up to 6 floors • Pathloss (dB, distance d in meter) n+2 − 0.46 Pathloss(dB) = PL (dB) + 0.7 d 2 D ,indoor + pAint + qAext + 18.3n n +1 • Within the same stripe PL (dB) = 38.46 + 20 log10 R • Otherwise PL (dB) = max{ 38.46 + 20 log10 R , 15.3 + 37.6 log10 R } • Shadowing • 4dB of standard deviation • No shadowing if d < 1mBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 24This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  25. 25. Femtocell Urban Model (2/2)• 5x5 Grid [3GPP TR.36.814] • 25 blocks • Pathloss (dB, distance d in meter) • No wall modelling Pathloss(dB) = 37 + 30 log10 ( d ) • Shadowing (dB) • 10dB of standard deviation • No shadowing if d < 1m • Aggressive femto-to-femto interference scenarioBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 25This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  26. 26. Femtocell & Users’ Drop• Femtocell deployment • Deployment probability inside a block • Random position inside one block • Users are dropped per deployed femtocell • Random position inside the same block • Minimum femto-user distance = 20cmBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 26This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  27. 27. Link to System • With fast fading, SINR is computed on each subcarriers • One SINR is derived using compression (MIESM, EESM) • From this SINR • Look-Up Tables (BLER vs SINR) • Enables realistic traffic modelling • HARQ … • Truncated Shannon Bound • Gives spectral efficiency min(η max , α log 2 (1 + SINR) SINRt > SINRmin ηt =    0 SINRt ≤ SINRmin η max = 4.4 SINR min ( dB ) = −10 α = 0. 6 BeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 27 This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  28. 28. Evaluation of Power ControlBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 28This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  29. 29. System simulation assumptions Parameter Value Parameter Value Total bandwidth 10MHz Number of 5x5 grids 21 Carrier frequency 2GHz Deployment ratio 15% Thermal noise density -174dBm/Hz Number of UEs per femto 4 Max FBS power 10dBm Inter-site distance 500m Min FBS power -10dBm Number of sites 7 External wall attenuation 20dB Number of sectors per site 3 Shadowing std deviation 10dB Number of UEs per sector 50 Shadowing correlation 0 Inside 5x5 grid ratio 35% Shadowing autocorrelation 3m MBS power 46dBm Shadowing std deviation 8dB Shadowing correlation 1 if same site between sectors 0.5 otherwise Shadowing autocorrelation 50mBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 29This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  30. 30. Static Evaluation - 5x5 Grid (1/2)• Independent CSG per femtocell 1 No PC - Macro - Avg=-0.29952, 5-perc=-22.1293 No PC - Femto - Avg=9.0862, 5-perc=-11.4683 0.9 PC(α =1,Lf=60) - Macro - Avg=2.0814, 5-perc=-9.7065 PC(α =1,Lf=60) - Femto - Avg=7.8147, 5-perc=-5.1789 Cumulative Distribution Function (cdf) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 -50 -40 -30 -20 -10 0 10 20 30 40 50 GFactor (dB)BeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 30This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  31. 31. Static Evaluation - 5x5 Grid (2/2)• Outage • One user is in outage if its G-factor is below -6dB• Independent CSG UE in outage (-6dB) No PC PC MUE 20.66% 8.99% FUE 10.80% 4.18% Average Tx power dBm No PC PC FBS 10 -1.1885• Common CSG UE in outage (-6dB) No PC PC MUE 19.76% 7.57% FUE 0.001% 0.06% Average Tx power dBm No PC PC FBS 10 -1.1885BeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 31This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  32. 32. System simulation assumptions (2) Parameter Value Parameter Value Total bandwidth 10MHz Number of dual-stripes 21 Carrier frequency 2GHz Deployment ratio 15% Thermal noise density -174dBm/Hz Number of UEs per femto 4 Max FBS power 10dBm Inter-site distance 500m Min FBS power -10dBm Number of sites 7 External wall attenuation 20dB Number of sectors per site 3 Internal wall attenuation 5dB Number of UEs per sector 50 Shadowing std deviation 4dB Inside dual-stripes ratio 35% Shadowing correlation 0 MBS power 46dBm Shadowing autocorrelation 3m Shadowing std deviation 8dB Shadowing correlation 1 if same site between sectors 0.5 otherwise Shadowing autocorrelation 50mBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 32This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  33. 33. Static Evaluation - Dual-Stripes• Independent CSG UE in outage (-6dB) No PC PC MUE 10.72% 3.05% FUE 1.32% 0.58% Average Tx power dBm No PC PC FBS 10 -1.3233• Common CSG UE in outage (-6dB) No PC PC MUE 10.36% 2.12% FUE 0.002% 0.02% Average Tx power dBm No PC PC FBS 10 -1.3233BeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 33This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  34. 34. Evaluation of Frequency Partitioning SchemesBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 34This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  35. 35. Fractional Frequency Reuse (FFR)• Cell space is divided in two: • Inner Region • Outer Region (edge users)• Edge users are given orthogonal subbands • SINR significantly increased • Bandwidth not fully used within one cell Inner Tx power W0 W1 W2 W3 Region Outer Region W0 W1 W0 W3 W0 W= W0+W1+W2+W3 W2 FrequencyBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 35This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  36. 36. Soft Frequency Reuse (SFR)• Cell space is divided in two: • Inner Region • Outer Region (edge users)• Edge users are given more power • SINR increased • Bandwidth fully used within one cell Inner Tx power W0 W1 W2 Region Outer Region W1+W2 W0 W0+W1 W2 W2+W0 W= W0+W1+W2 W1 FrequencyBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 36This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  37. 37. Resource Allocation in LTE Rel.8/9 RBG RB #0 #0 #1 #2• In LTE, the total bandwidth (BW) is divided Subband #1 #3 #4 #5 in many parts of increasing size Bandwidth part 0 Subband #0 • Resource block (RB) #2 #6 #7 #8 #3 #9 #10 #11 • 1RB = 12 subcarriers Subband #1 • Resource block group (RBG) #4 #12 #13 #24 • 1RBG = set of contiguous RBs Subband #2 #5 #15 #16 #17 • Subband (SB) #6 #18 #19 #20 Bandwidth part 1 Subband #0 • 1SB = set of contiguous RBGs #7 #21 #22 #23 • Usually 1SB = 2 RBGs Subband #1 #8 #24 #25 #26 • Bandwidth part (BP) #9 #27 #28 #29 • 1BP = set of contiguous SBs Subband #2 #10 #30 #31 #32• Example @10MHz in DL #11 #33 #34 #35 • BW = 3BPs = 9SBs = 17RBGs = Subband #0 Bandwidth part 2 50RBs = 600 subcarriers #12 #36 #37 #38 Subband #1 #13 #39 #40 #41• Allocation Type 0 allows one user to have any set of RBGs #14 #42 #43 #44 Subband #2• However, user’s reporting has a subband #15 #45 #46 #47 granularity #16 #48 #49BeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 37This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  38. 38. Example of FFR/SFR in LTE Rel.8/9• FFR: 2 subbands per outer region• SFR : 2 subbands per outer regionBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 38This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  39. 39. Macrocell Only• Comparison between FFR, SFR and Reuse 1 (IFR)• FFR scheme improves significantly the SINR • May be a good candidate for macrocell partitioningBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 39This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  40. 40. System simulation assumptions Parameter Value Parameter Value Total bandwidth 10MHz Number of dual-stripes 5 Carrier frequency 2GHz Deployment ratio 10% Thermal noise density -174dBm/Hz Number of UEs per femto 1 FBS power 20dBm Inter-site distance 500m External wall attenuation 20dB Number of sites 7 Internal wall attenuation 5dB Number of sectors per site 3 Shadowing std deviation 4dB Number of UEs per sector 7 Shadowing correlation 0 MBS power 46dBm Shadowing autocorrelation 3m Shadowing std deviation 8dB Number of subbands used 2 Shadowing correlation 1 if same site for data between sectors 0.5 otherwise Shadowing autocorrelation 50m Number of subbands for the 1 outer regionBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 40This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  41. 41. Dynamic Evaluation - MIMO• Cell throughput 1 0.9 0.8 Cumulative Distribution Function (cdf) 0.7 0.6 0.5 0.4 0.3 Macro 1x1 - Avg=14.2392, 5-perc=9.1579 0.2 Femto 1x1 - Avg=8.7766, 5-perc=5.3088 Macro 2x2 - Avg=22.2534, 5-perc=14.3447 Femto 2x2 - Avg=16.2933, 5-perc=8.4446 0.1 Macro 4x4 - Avg=39.1508, 5-perc=25.4384 Femto 4x4 - Avg=30.5246, 5-perc=13.6049 0 0 10 20 30 40 50 60 70 Cell Throughput (Mbits/s)BeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 41This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  42. 42. Dynamic Evaluation - MIMO• Mobile throughput 1 0.9 0.8 Cumulative Distribution Function (cdf) 0.7 0.6 0.5 0.4 0.3 Macro 1x1 - Avg=2.0342, 5-perc=0 0.2 Femto 1x1 - Avg=8.7766, 5-perc=5.3088 Macro 2x2 - Avg=3.1791, 5-perc=0 Femto 2x2 - Avg=16.2933, 5-perc=8.4446 0.1 Macro 4x4 - Avg=5.593, 5-perc=0 Femto 4x4 - Avg=30.5246, 5-perc=13.6049 0 0 10 20 30 40 50 60 Mobile Throughput (Mbits/s)BeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 42This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  43. 43. ConclusionsBeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 43This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
  44. 44. Conclusions• Spectrum being a scarce resource, frequency reuse is of major interest• Under such co-channel deployment, interference management is a crucial factor for Heterogeneous Network success• For LTE / LTE-A, control and data channels need to be protected • Due to their positioning within one subframe, different schemes have been developed (time/frequency domain)• Use of system-level simulations allows a large scale performance evaluation of interference management (for data & control channels)BeFEMTO Winter School | SCET/URD1/Femtocell | Interference Management in Co-Channel Femtocell Deployment | © Sagemcom 44This document and the information contained are Sagemcom property and shall not be copied or disclosed to any third party without Sagemcom prior written authorization
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