ZTE’s C-RAN Progress in China
WWRF
Challenges facing by CMCC in Network Evolution Network Pressures
Building Acquisition and constructions
Review RAN Architecture
Capacity vs. Quality
High Opex and Capex High Energy consumption
Challenges in Evolution GSM
GPRS EDGE
eEDGE TDSCDMA WCDMA R99
HSPA+ HSPA MBMS HSDPA R5
HSUPA R6
HSPA+ R7
MBMS cdma 1X
TDD L T E
4G FDD
cdma 2000 cdma 2000 EV-DO EV-DO Rev. A EV-DO Rev. B 802.16 d
Site density increase due to fast increasing traffic
Interference problem limits network Capacity
802.16 e
802.16 m
Dynamic workload Low BS utilization rate
C-RAN leverage 4G technology in 2G network Core
Aggregation
Access
CATV Fixed Service Server
IPTV
softswitch
Packet Transport MSTP/SDH/DWDM
Internet
RNC GGSN SGSN HLR
MSC Server
Mobile
MGW
GE/ 10GE
Milestones for C-RAN Development Published C-RAN V1.0 Standard China Mobile R&D Institute held International C-RAN Forum, issued white paper on C-RAN and signed MoM with IBM, Intel, ZTE, Huawe i for stratigic cooperation. ZTE SVP Zhao Xian Ming attended the ceremony.
Super BBU Pool Technical Meeting Meeting held with Group Wireless R&D Institure, focusing on centrialization and cost reduction.
2010.1.12
2010.2
2010.4.27
2010.10
Specific meeting held for reporting progress to Li Yue Specific C-RAN report meeting to Li Yue was held when he was visiting ZTE R&D Centre in Sweden. ZTE leading position on high capacity & less sites were acknowledged by Li Yue, who also asked to accelerate development of standard and pushed for field trial.
2010.11.9
Large Scale Application 2011.7 ChangSha Trial 2011.8 BaoDing Trial
2010.12.15
2011.7
Super BBU Pool Deployment For an area with 568 BBU and 2337 RRU, Super BBU Pools were used for a commercial network. CAPEX was reduced 20%+ and OPEX was reduced 60%+。
ZhuHai C-RAN Commercial deployment announced
Published C-RAN V2.0 Standard
ZhuHai TD C-RAN commercial deployment announced, Group R&D Institute and Local OpCo held joint News Conference at the site. Senior leaders from Industry and Information Department were invited to attend.
China Mobile R&D Institute, together with ZTE, IBM, Intel, Ericsson, NSN and Huawei held International C-RAN Forum again at the 4th Mobile & Internet International Conference and MOU was signed.
C-RAN Trial Target
Centralize
BBU
BBU Pool BBU addition or deletion without service interupt
RRU
Environment Monitoring Equipment monitoring CPRI Monitoring
Ring Topology
18 RRU cascaded To save fiber resource Detection of Ring Topology configuration Detection of RRU addition or deletion
Cooperative
Tidal Traffic
Radio
Migration
Multi RRU in one Cell
Tidal Traffic migration
Basic configuration validation Performance Validation Reduce interferences
This function Performance Statistics report Threshold setting of carrier resource allocation and release Baseband resource allocation and release
Performance
TCO Reduction
Improvement
C-RAN site driver test C-RAN site KPI analysis
Main Targets of this trial
Large site validation Medium site validation Small site validation
Project Overview - The Covered Area A Shangyoucun
Library of Hunan Normal University
Tianmashan BBU pool
D
about 15
km2, mainly university area including HuNan Normal University,
Twilight Garden
ZhongNan
B South area of HUT
coverage
C
University
Feng’s old houses Shenghua apartment
Houhu neighborhood
Jinjiang garden Jinjiang neighborhood
West Sanqiao
Sunshine garden
11 sites, among
them 9 existing sites,2 new built sites.
Project Overview－Network Topology Feng’s Old Houses
West Sanqiao
Sunshine Garden
Zhengjiawan
Jinjiang Garden
Jinjiang Neighborhood Houhu Neighborhood (new 900M site) South Area of Hunan University of Tech. (900/1800M coco-site)
Tianmashan BBU Cabinet Xinmin Rd.
Shangyoucun
Shenghua Apartment (900/1800M coco-site)
Twilight Garden (new 900/1800M site, outdoor + indoor distribution)
Library of Hunan Normal University (900/1800M coco-site))
Before Swap
After Swap
Fiber Connection - 18 Levels RRU Daisy Chain 18 RRU Site Name
Configuratio n
Houhu neighborho 900M 7/7/7 od Shenghua apartment South area of HUT
900M RRU
1800M RRU
3
0
3
8
3
1
Total
900M 8/6/8 1800M 8/8/8/8/8 900M 8/6 1800M 6
OSS configuration Interface
TianbaoShan BBU Central Office BBU2
18
18 RRU daisy chain 3 RRU in Houhu neighborhood site
4 RRU in South area of HUT
11 RRU in
Shenghua apartment site
Access Loop B is 18 level RRU daisy chain， chain， the basestation function and Delay compensation test is passed in this test.
Ir Interface Direct Fiber Connection Centralized BBU Pool
RAN.
Quantity of Twin-core fiber is the same as the traditional fiber transmission solution.
Access Ring of Fiber
Just a pair of fibers can be realized GSM C-
Support 60 Km distance, can meet the requirement of different scenario.
6G White Fiber is used in Changsha GSM CRAN trial.
Compared with the Tradit ional networking which is SDH access ring, still need only one pair fibers for connecting the same quantity of site, no need to change the transmission archetecture
RRU Ring topology
Total 108 carriers sector share the BBU resource
Ring topology can support high availability of serivice.
Automatical switch while the link is brokean or one RRU is down
Swithch time : 136ms
During the link switch, service is not interrupted
Effective Baseband Dynamic management CS Traffic in busy hour(erl)
Allocated Baseband Resource
180
80
160
70
140
60
120
Peak traffic is 159Erl at 22:00, and the allocated baseband resource of BBU is 62 which is also maximum.
50
100
40
80
30
60
7:00 8:00
5:00 6:00
3:00 4:00
1:00 2:00
23:00 0:00
21:00 22:00
20:00
18:00 19:00
16:00 17:00
0 14:00 15:00
0 12:00 13:00
20
10 10:00 11:00
20
9:00
40
Lowest traffic is 0.37 Erl at 4:00 , and the allocated baseband resource of BBU is 23 which is also the minimum.
In traditional network-mode, the baseband and RF resources is 1:1 mapping, with resource can not be fully utilized. In C-RAN, baseband resources are allocated according to traffic, high traffic with more allocated resources, low traffic with less allocated resources. So the resource resource utilization rate is much higher.
Solve the problem of Tidal Traffic Migration There are tidal traffic in Shenghua apartment site area from 21:15 to 22:45. Students return to their appartment after class, the traffic in the apparment area increased CS Traffic of Classroom buildings Area(erl) Allocated Baseband resource of Classroom buildings Area 20 18 16 14 12 10 8 6 4 2 0 19:0019:1519:3019:4520:0020:1520:3020:4521:0021:1521:3021:4522:0022:1522:3022:4523:0023:1523:3023:45 0:00
Traffic migration in the night, the traffic of student
Baseband resource allocate dynamically while
appartment increased while students returns to their
there are traffic migration, the resource migrate
appartment.
from classroom buildings to appartments and the total baseband resource nearlly keep the same.
Multi-RRU for one cell for coverage reshaping Technicl Implementation
Multi-RRU in one logic cell , cover different area “Reshaping” increases downlink coverage and improves uplink reception
Principle Description
New Combined Cell
Original cell
Reuse Existing site Use nearby existing sites, “reshaping”the coverage at the targeted area, this reduces the requirement for new sites at weak coverage area.
Technical Value
C-RAN architecture can make flexible site type adjustment, allocate power according to requirement and realize seamless coverage. Cooperative planning, traffic balancing, avoiding network congestion. Multi RRUs forming a logical cell can simplify network structure, reduce handovers and improve network quality.
Suburban Wide Area Coverage Multi layer “reshaping”through using multi RRUs to form a logical cell to increase the cell coverage radius.
Picture of Current Network Site
Handover reduced 50% . Traffic increased by 40%
Befor e After
Covera ge ratio
Voice quality
Ratio of HO coding
Residential Area Coverage 1 RRU connected to the disguised antenna, covering the main road by the river
3 RRU mounted on the top of the building for indoor coverage
Using indoor distributed system and ceiling mounted antennas for underground garage coverage
2 RRUs connected to the disguised antenna, covering the resident-ial area, one of the RRU forming a logical cell with an indoor RRU Since indoor RRUs and outdoor RRUs forming one logical cell, through cooperation among RRUs no handover will happen when getting into and coming out from underground garages, lifts and flats.
Number of handovers in a cell
Average MOS value
Average ratio for UL RQ0-3
UL RQ0-3 improves 1%
Average ratio for DL RQ0-3
Without multi RRUs Multi RRUs forming a logical cell forming a logical cell
Without multi RRUs Multi RRUs forming a logical cellforming a logical cell
DL RQ0-3 improves 2.5%
Network Performance Improvement - CQT CELL
CI
Before Swap
After Swap
36781
104.33
120.17
Feng’s old houses ZG-2
36782
143.59
135.56
Feng’s old houses ZG-3
36783
85.62
145.6
35401
121.15
123.28
35402
121.65
145.9
35403
112.12
134.03
Sunshine garden ZG-1
42071
98.24
116.6
Sunshine garden ZG-2
42072
63.32
157.37
Sunshine garden ZG-3
42073
132.12
135.43
West Sanqiao ZG-1
25151
126.4
168.23
West Sanqiao ZG-2
25152
113.45
124.2
West Sanqiao ZG-3
25153
125.87
178.45
Jinjiang garden ZG-1
54651
117.68
156.2
Jinjiang garden ZG-2
54652
130.2
171
Jinjiang garden ZG-3
54653
108.76
148.79
Improved significantly
Feng’s old houses ZG-1
Jinjiang neighborhood ZD-1 Jinjiang neighborhood ZD-2 Jinjiang neighborhood ZD-3
Data service quality also improved greatly, FTP download rate increased by 26.7%
FTP Download Rate（Kbps）
Ring C
Summary
With C-RAN , CAPEX saving 27.1% , OPEX saving 63.9% Performance improved , download speed increased 26.7% , voice quality improved . And it’s a future prove , green network .
