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NTT DOCOMO Field ExperimentsNTT DOCOMO Field ExperimentsField experiments have been conducted in 3 cities in Japan to confirm LTE practical performance in variety of environments
Yokosuka, Kanagawa• Started in February, 2008• 2 sites, 2sectors/site• Rural environmentKofu, Yamanashi
• Started in August, 2008• 2 sites, 6 sectors/site• Suburban environment
Sapporo, Hokkaido• Started in October, 2008• A single site, 2 sectors• Urban environment
Throughput fluctuations depend on SINR fluctuationsAt point a (400 m from eNB antenna), more than 200 Mbps achievedAt point b, throughput degrades due to low SINR
Field trial results are worse than those of lab test by several dB due to antenna correlation4x4 MIMO outperform 2x2 MIMO or SIMO significantly2x2 MIMO outperform SIMO under high SINR environment
More Detailed Results of LTE TrialsMore Detailed Results of LTE Trials
Y. Ofuji, et al., “Experimental Results of E-UTRA Downlink with Variable RB Allocation,” IEEE VTC 2008-Fall, Sep. 2008.N. Okubo, et al., “Experimental Results of E-UTRA Uplink with Variable RB Allocation,” IEEE VTC 2008-Fall, Sep. 2008.Y. Ofuji, et al., “Experimental results on 4x4 MIMO precoding in E-UTRA, ” The 14th Asia-Pacific Conference on Communications (APCC) 2008, Oct. 2008.Y. Ofuji, et al., “Field Experimental Results of E-UTRA Downlink with Precoding and Non-Precoding MIMO, ” IEEE VTC 2009-spring, to be submitted.H. Takahashi, et al., “Field Experimental Results on E-UTRA Downlink Throughput Using Polarization Diversity Antennas, ” IEEE VTC 2009-spring, to be submitted.
Status toward LTE introduction in Status toward LTE introduction in JapanJapan
Introduction of 3.9G mobile communications system has been studied in telecommunications council in Japan since April 2008
In the council, LTE was proposed as one of 3.9G system to be studiedAs the study results, feasibility of LTE was confirmed in terms of meeting requirements of 3.9G and co-existence with existing radio systemsFour cellular operators in Japan, including DOCOMO, declared to introduce LTE as the 3.9G system within several yearsNTT DOCOMO declared to launch LTE in 2010 as one of the leading companies of LTE in the world
Overall LTE Time Plan of DOCOMOOverall LTE Time Plan of DOCOMO((Assumption with current 3GPP work plan)Assumption with current 3GPP work plan)
2006 2007 2008 2009 2010
▲▲Core spec approval
Experimental System
▲RFP
3GPP Standardisation
development
▲Core spec freezing
Commercial System Development
System Development
Indoor/FieldExperiments & Demo
2006 2007 2008 2009 2010
DoCoMo aims to complete the technology development before the end of 2009.
CommercialDeployment
Target date of development
completion: By the end of 2009
DOCOMO aims to complete the technology development before the end of 2009.To ensure the roaming/interoperability, we will watch the global status carefully and make a concrete plan.
LTE TrialsNTT DOCOMO conducted LTE indoor and field trials from July 2007 and February 2008, respectively.Field trials are conducted in 3 cities in Japan to confirm practical LTE performance under variety of environmentThe trial results shows satisfying high performance of LTE in terms of delay, throughput and stability
NTT DOCOMO’s views on LTE deploymentNTT DOCOMO will launch LTE in 2010 as one of the leading companies of LTE in the worldLTE service area will be overlaid with 3G service area and LTE/3G dual mode terminal will be introduced in order to deploy seamless service area from the beginning of LTE launch2 GHz spectrum band will be used for LTE launch considering utilization of existing NW facilities and global roamingLTE spectrum can be increased in the future according to wide spread of LTE terminals and new spectrum band allocation