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4.5G: boost the experience from user and operator’s perspective Dr. Guangyi Liu CMCC

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PowerPoint operator’s perspective
Dr. Guangyi Liu
Base Station
Terminal (10^8)
2014 up to now 2014 Total 2014 up to now 2014 Total
International roaming with 8 operators
Better experience for users with video services
Guarantee roaming based on robust ecosystem
2012 2013
Phase 2,2014
Features in Trial
Band 39:TDD
825 835 870 880 889 915 934 960 909 954 1710 1755 1785 1850 1735 1830 1880 1805
Band 3: FDD Band 3: FDD Band 8: FDD Band 8: FDD FDD FDD
2025 2010
B34: TDD
2400 2300
Band 41: TDD
Band 39: 1880-1900MHz for TD-SCDMA&TD-LTE
Band 40: 2320-2370MHz for TD-SCDMA&TD-LTE (indoor only)
Band 41: 2575-2635MHz for TD-LTE
Note: 1785-1805MHz has limited applications for broadband wireless access,
e.g. providing BWA service in some airports
increase bandwidth efficiency
Object: Guarantee coverage and
bandwidth efficiency
For the first 2 phases, the industry is mature enough for commercial deployment
The convergence can be further enhanced by deploying TDD/FDD joint operation
in the near future
Well supported by both network equipment/terminal industry, ready for commercial deployment. All
5-mode or 4-mode smartphones can support handover between TD-LTE and LTE FDD
since H2 of 2013
Phase I: Coverage-based Mobility Management
Industry & Commercial Deployment Status
Idle Reselection success rate: 100%, latency~31 ms
Handover success rate 100% control plane latency 16~18 ms user plane latency55~56 ms
Performance at the same level as inter-frequency handover within TDD or FDD
Performance in China Mobile Hong Kong (CMHK)

Network equipment: well supported, ready for commercial deployment
Terminal: no additional requirement needed as long as UE supports TDD/FDD handover,
well supported
load evaluation/user selection/user transfer/load information exchange, which
might degrade the performance. Definitions needs to be unified to enhance user
experience/network efficiency during load-balancing handover
Notes on Commercial Deployment
be done when needed
Scenario2 TDD-FDD non-co-baseband, multi-vendor
Non-ideal backhaul
(e.g., X2)
Phase III: Joint Operation
• Peak data rate (theoretical): 20M TDD+20Mx2 FDD = 260 Mbps • Dynamic load balance (CA, ~ms level): 10% ↑ cell average throughut (simulation)
30% ↑ cell edge throughput (simulation)
Standardization Progress & Industry Status
• Standard Progress: Both TDD-FDD CA and Dual Connectivity are ongoing in 3GPP R12; • Industry status: Initial PoC and field trial has been done by some network vendors;
Finished B8900M+B402.3G B12.1G+B423.5G B19850M+B423.5G
Ongoing B12.1G+B412.6G B31.8G+B402.3G B26850M+B412.6G B31.8G+B412.6G
Industry Status of TDD-FDD Joint Operation
TDD as PcellDL peak data rate 250Mbps
FDD as PcellDL peak data rate 250Mbps
PoC demo of TDD-FDD CA in MAE 2014 Field Trial of Dual connectivity in Shanghai
MSA enhances the peak data rate and cell-edge throughput
MSA balance load between Macro and small cell by load and inteference condition
Peak data rate Cell-edge throughput
Balance by load Balance by interference
• 20M TDD config.2 band41+ 20*2 FDD(band8); • Both TDD and FDD can be configured as Pcell;
TDD-FDD CA enhance peak data rate
• 10M TDD 3.5G+ 10*2 FDD (2.6G);
Insufficient deep indoor coveragehigh cost by deploy DAS
Co-exist of multi-band
and multi-system need
to be considered
Hard to obtain or to get site locations for macro cells
Flexible eNB types would be helpful !
Flexible eNB types is the way for deep coverage
Macro cell Micro cell Pico/Nanocell Nanocell
Macro coverage dead spot and
hot spot coverage Home coverage
Public indoor coverage
Mobile data traffic exploding
• ~5X small cells vs. macro cells
without new frequency introduced
with new frequency introduced
More dependent on SON Complex interference control
& mobility management
multi-RAT coordination, TDD/FDD joint
Find new resources, e.g.
Improve the capability , e.g.
Spectrum Flexibility
IILoad Balancing
MRC (Multi-RAT Connectivity)
The first and second phase of FDD/TDD convergence has been tested, and coverage
based handover and load balance could be introduced
2014/10/20 20
Carrier Aggregation is supposed to be the only solution for LAA at least in R13
Carrier Aggregation Standalone
Perform interference handling Avoid congestion on unlicensed band Guarantee QoS Separate signaling and data
Possible for normal UE to deploy LTE Hard for interference handling
Licensed Band Unlicensed Band
• Not so much potential spectrum available for IMT below 6GHz
• Spectrum will be the most important aspect for IMT development
• Unlicensed spectrum requirements
• Spectral efficiency limitation for uplink transmission – E.g., maximum 16QAM or 64QAM, which limits higher transmission spectral efficiency
regardless higher transmission power
– Tx EVM limits higher SINR at receiver side, which limits higher transmission spectral efficiency
For example, ~90% users has SINR higher than MCS_16 - Assuming maximum 16QAM, 1Tx8Rx
~50% users has SINR higher than MCS_16 - Assuming maximum 16QAM, 1Tx2Rx
• Possible enhancement, especially for good SNR users • Uplink Dual Transport Blocks (TB) transmission for 1Tx UE (UL_1Tx_dualTB) can
offer gains from uplink peak data rate and spectral efficiency perspective[1]
• Utilization of uplink 64QAM (UL_64QAM) [2] Note:
[1] RP-140663 New Work Item Proposal: support of uplink 64QAM in LTE Huawei, HiSilicon
[2] RP-141287 Uplink dual transport block transmission to enhance uplink performance CMCC
Wide beam in elevation domain Narrower beam in elevation domain
Fixed downtilt Larger downtilt for cell-center user
Can separate users in horizontal domain only
Can separate users in both horizontal and vertical domain
The aim is to improve the radio access control and user data transmission in a
differentiated manner on a service-aware basis.
Service-Aware Management
User data management optimization
• Popular service cached in RAN side
•Reduce backhaul and Core load RAN Caching
•Adaptive service distribution and convergence
•Consistent service experience Service continuity
• Finer gratuity of QoS handling w.r.t. signaling and user data treatment
Small Cell Enhancement
Dual connectivity
Average spectrum efficiency 16%↑
Maximum +/- 1.5us timing error supporting 4 stratum levels Supporting network listening between inter-vendor small cells
User peak throughput 90%↑
Non-idea backhaul
Cell discovery
Small cell on/off
· Cell 1 (on) · Cell2 (off) · Cell 3 (off) · Cell 4 (on)
· Cell 5 (off
most operators is this year • SINR: Be used to detect
coverage problems and access network performance
• Towards eMDT • Specify VoLTE and video related
measurements and corresponding collection.
– Decrease the cost of drive testing
– Avoid additional emission of CO2
– Extend time and space for drive testing
Voice Related Enhancement
• CSFB: UE automatic fast return after CSFB to GSM – Save the delay of returning LTE (about
0.4-1.9s), while the cell reselection delay is more than 40s
– Standardization needed, both CSFB to GSM and 3G
• VoLTE SPS: Unsatisfied Performance – Standard limitation on max MCS (below 15) – Scheduler has to be prepared for long term (e.g.200 ms) RF condition thus
sacrifice too much radio resource – Clarification needed for SPS + C-DRX
• eSRVCC: long preparation time & interruption time – prep time(asking 2G for resource reservation) takes 1 - 2s due to long signaling chain, making HO vulnerable to failure – User plane interruption time up to 800ms, optimization needed
• Converged FDD/TDD networking becomes a trend
• Heterogeneous network is the flexible way for deep coverage and capacity expansion
• Further enhancement is expected to
– boost the network capacity and user experience
– simplify the network optimization and maintenance