1. Interference Management in LTE and CoMP Transmission
From dream to reality
Interference Management in LTE and CoMP Transmission
Presented by
Sheng Gao, 84937J
Supervisor: Professor Jyri Hämäläinen
Instructor: Ph.D Alexis Alfredo Dowhuszko

2. General Thesis Information
Introduction of LTE and LTE-A
ICIC and eICIC
CoMP
Conclusion

3. 1. LTE 100M bits/s downlink 50M bits/s uplink on 20M Hz bandwidth
Architecture
Key technologies
OFDM: multi-carrier
MIMO: precoding, multiplexing, diversity.
SC-FDMA in Uplink

4. LTE-Advanced
Relay
Carrier aggregation
Enhanced MIMO
CoMP

5. 2. Interference Analysis
Inter-systems Interference
Example: China
Intra-LTE interference
Inter cell interference
Traditional interference mitigation methods
Interference randomization
Interference cancellation
including addressing page/section breaks and dealing with landscape tables.
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6. ICIC LTE Release 8, balance network and allocate resources.
Fractional Frequency Reuse (FFR)
Soft Frequency Reuse (SFR)
UE 1
UE 2
UE 3
UE 4
 Cell 1
Cell 2 
Cell 3 
UE 5
 Cell 1
Cell 2 
Cell 3 
Edge region
including addressing page/section breaks and dealing with landscape tables.
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Central region
Full Frequency Reuse

7. eICIC Mainly for Heterogeneous network in LTE-A Macro cell subframes
UE1 can be scheduled in these ABS to pico cell
Macro cell subframes
including addressing page/section breaks and dealing with landscape tables.
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8. 3. CoMP 3GPP Release 10 For cell edge users
including addressing page/section breaks and dealing with landscape tables.
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9. CoMP method: CS/B Both in downlink and uplink
including addressing page/section breaks and dealing with landscape tables.
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10. CoMP method: Joint Processing
Dynamic Point Selection
CSI are always collected to find best channel
Joint Transmission
Non-coherent JT
Coherent JT
including addressing page/section breaks and dealing with landscape tables.
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11. Joint Transmission Non-coherent JT Coherent JT
including addressing page/section breaks and dealing with landscape tables.
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12. Scheduling Classic scheduling algorithm Centralized Joint Scheduling
Round Robin Algorithm
Max C/I algorithm
Proportional fairness algorithm P= 𝐷 𝑖 (𝑡) 𝑅 𝑖 (𝑡) ,
𝑅 𝑖 𝑡+1 = 1− 1 𝑇 𝑅 𝑖 𝑡 + 𝐷 𝑖 (𝑡) 𝑇
Centralized Joint Scheduling
Virtual cell
Same available physical resource block will be scheduled.
including addressing page/section breaks and dealing with landscape tables.
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13. Challenges Backhaul: X2 to optical fiber Synchronization
Feedback and CSI
Explicit feedback
Implicit feedback
Feedback based on SRS: TD-LTE
including addressing page/section breaks and dealing with landscape tables.
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14. Future Research Enhanced CoMP by Samsung
With non-idea backhaul
Support coordination among eNodeBs from different vendors
Two stages resources allocation
Resources coordination
Central resource coordinator decides which TP gets which frequency or time resources
UE selection and link adaption
Each TP runs channel opportunistic scheduler based on latest CSI from UEs
including addressing page/section breaks and dealing with landscape tables.
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15. 3. Conclusion
ICIC and eICIC with Het-net structure can greatly reduce ICI.
Although hard to realize currently, CoMP is fabulous and point out the development direction.
including addressing page/section breaks and dealing with landscape tables.
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17. Thank you!
Questions?
including addressing page/section breaks and dealing with landscape tables.
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