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FDD-LTE Radio Link Budget

Content

FDD-LTE link budget overview
FDD-LTE UL Link budget
FDD-LTE DL Link Budget
Cell radius and areas


FDD-LTE link budget overview 

The process of FDD-LTE network planning


Link budget input and output


Normal Link budget requirements


Link budget model






Shannon formula


FDD-LTE UL Link budget

UL Link budget process


UL link budget Methodology



Assigned  RB number


Number of Resource Blocks

For a given MCS the TBS is given different numbers of resource blocks


Modulation & Coding Scheme

This determines the Modulation Order which in turn determines the TBS Index.


TBS and MCS


Assign RB number


SINR
  • SINR Target depends on: 
    • eNode-B equipment performance 
    • Radio conditions (multipath fading profile, mobile speed) 
    • Receive diversity (2-way by default or optional 4-way) 
    • Targeted data rate and quality of service 
    • The Modulation and Coding Scheme 
    • Max allowed number of HARQ transmissions (Maximum of 4 on UL) 
    • HARQ BLER target (10% considered by default) 
  • Derived from link level simulations or better by equipment measurements (lab or on-field measurements)

Assign RB number


Rx receive sensitivity


Thermal Noise


Receiver sensitivity



UL Interference Margin


UL Interference Margin




Four Antenna configuration way






TMA gain



Shadowing Margin



Hard handover Gain



Penetration loss


Body loss




Propagation model




FDD-LTE DL Link Budget

Different of UL and DL link budget


DL link budget Methodology


DL Link budget character


DL link budget approach


  • Base on the UL link budget result decide the cell range. 
  • Base on the decided cell range, get DL path loss at cell edge 
  • Base on DL path loss and considered DL Tx power and total other gain & loss to get DL signal power at cell edge. 
  • According Geometry factor at cell edge to get other cell interference 
  • Base on DL signal power and other cell interference and noise to get DL SINR at cell edge. 
  • Base on DL SINR at cell edge and the DL bandwidth and available RB number to decide the MCS and TBS, and then, get the DL throughput at cell edge.


DL shadowing Margin



Adjacent Tx Power load



Geometry factor



SINR



DL Link budget




DL Link budget approach



Cell radius and areas

Limited link


Cell range and inter site distance


Glossary

  • RB: Resource Block 
  • TBS: Transport Block Size 
  • MCS: Modulation & Coding Scheme 
  • SINR: Signal to Interference plus Noise Ratio 
  • MIMO: Multiple Input Multiple Output 
  • MAPL: Maximum Allowable Path Loss 
  • TMA: Tower Amplifier 
  • BLER: Block Error Ratio 
  • HARQ: Hybrid automatic repeat request 
  • SNR: Signal to Noise Ratio 
  • NF: Noise Figure 
  • ISD: Inter-station Distance 
  • CDF: Cumulated Distribution Function 
  • TTI: Transmission Time Interval
End of Course