interference management in lte and comp transmission presented by sheng gao, 84937j...
TRANSCRIPT
Interference Management in LTE and CoMP Transmission
Presented by
Sheng Gao, [email protected]
Supervisor: Professor Jyri Hämäläinen
Instructor: Ph.D Alexis Alfredo Dowhuszko
From dream to realityFrom dream to reality
General Thesis Information
Introduction of LTE and LTE-A
ICIC and eICIC
CoMP
Conclusion
1. LTE
UE eNode B
S-GW P-GW
MME HSS
PCRF
IP service
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
LTE-Advanced
Relay
Carrier aggregation
Enhanced MIMO
CoMP
eNodeB
Relay Node
MME
S-GW P-GW
eNodeB
2. Interference Analysis Inter-systems Interference
Example: China Intra-LTE interference
Inter cell interference
Traditional interference mitigation methods Interference randomization Interference cancellation
ICIC
Fractional Frequency Reuse (FFR)
UE 1
UE 2
UE 3
UE 4
Cell 1
Cell 2
Cell 3
UE 5
Soft Frequency Reuse (SFR)
Cell 1
Cell 2
Cell 3
Central region
Edge region
LTE Release 8, balance network and allocate resources.
Full Frequency Reuse
eICIC Mainly for Heterogeneous network in LTE-A
UE1 can be scheduled in these ABS to pico cell
Macro cell subframes
3. CoMP 3GPP Release 10 For cell edge users
CoMP method: CS/B Both in downlink and uplink
eNodeB
eNodeB
eNodeB
CoMP method: Joint Processing Dynamic Point Selection
CSI are always collected to find best channel
Joint Transmission
Non-coherent JT
Coherent JT
Joint Transmission
Non-coherent JT
eNodeB eNodeB
A2,B2,C2
Core network
A1,B1,C1
A,B,C for UE1
UE1 UE2
X,Y,Z for UE2
X2,Y2,Z2
X1,Y1,Z1
Data, CSI
Coherent JT
Scheduling Classic scheduling algorithm
Round Robin Algorithm
Max C/I algorithm
Proportional fairness algorithm ,
Centralized Joint SchedulingVirtual cell
Same available physical resource block will be scheduled.
Challenges
Backhaul: X2 to optical fiber
Synchronization
Feedback and CSI Explicit feedback Implicit feedback Feedback based on SRS: TD-LTE
Future Research
Enhanced CoMP by Samsung
With non-idea backhaul Support coordination among eNodeBs
from different vendors
Two stages resources allocation1. Resources coordination
Central resource coordinator decides which TP gets which frequency or time resources
2. UE selection and link adaptionEach TP runs channel opportunistic scheduler based on latest CSI from UEs
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.
Revealing Your Formatting
Questions?
Thank you!