2 Developing the standard on the evolution of the 3G mobile system –The evolution of the 3G radio-access technology towards a high-data- rate, low-latency and packet-optimized. –The main work of LTE focuses on: Architecture eNB function Radio interface Band arrangement Transmission scheme RF related requirements Mobility and RRM SON Support of Interworking between LTE and 3GPP RAT or 3GPP2 RAT –Currently focusing on LTE Stage 3 (finishing LTE Rel-8 specification) Highlight of Current Activities (1)
3 Highlight of Current Activities (2) Currently specifications completion level Transmission scheme Multiple Address 100 Downlink: OFDMA Uplink: SC-FDMA Frame Structure 100 Modulation 100 Coding 100 Physical procedure(99%) Radio interface and protocols MAC(80%) RLC(70%) RRC(70%) Architecture and protocols Architecture and Interface Protocol Structure(100%) RRM(90%) O&M(100%) SON(70%) MM(99%) RF related, band arrangement RF related requirement, the requirement support of RRM (80%) LTE repeater(25%)
4 Strategic Direction Growing experience with the take-up of 3G is helping to clarify the likely requirements of users, operators and service providers in the longer term LTE project aims to ensure the continued competitiveness of the 3GPP technologies for the future The LTE standards development had been defined in the following phases: –SI phase: finished at the Sep, 2006 –WI phase: started at the June, 2006 –Currently it is in Stage 3 in WI phase. It is expected to launch the first LTE commercial version standard by the end of 2008. In 2009, the work will focus on the enhancement and Improvement of LTE.
5 Challenges LTE business development and business model need more deep consideration because of HSPA+ and Wimax. With HSPA (downlink and uplink), UTRA will remain highly competitive for several years, most of operators are deploying 3G (UMTS/HSPA) network but have little income, it will be solved firstly. LTE performance can not be satisfied by some operators. So LTE system will be continued to be improved to fulfill the operators different requirements. The final choice of LTE technologies is not simply technological, it may be determined ultimately by IPR issues, there isnt a IPR solution till now. There are so many players in 3GPP which will take some difficulties to average benefit, So the schedule of LTE has been strongly delayed, It will be completed on Dec 2008.
6 Next Steps/Actions Begin the Study Item of LTE-Advanced, It shall be an evolution of LTE. –LTE terminal shall be supported in LTE-advanced networks –an LTE-Advanced terminal can work in an LTE part of the network Allow coverage ranging from Macro cells to indoor environment such as Home coverage Primary focus of LTE-Advanced is low mobility users Self-configuration and optimization shall be further enhanced Features already supported in previous releases are a pre-requisite for being supported by LTE-advanced LTE-advanced shall support FDD and TDD mode of operation with maximum commonality Cost reduction Low cost of the infrastructure deployment and terminal for LTE- advanced shall be an essential element Power efficiency in the infrastructure and terminal shall be an essential element Backhauling shall minimize cost per bit Minimizing additional complexity for the terminal
9 Huaweis activities in LTE Huawei is one of the pioneer companies who proposed the creation of LTE. We now have plenty of important proposals accepted involving in physical layer, high layer, interface and performance. Huawei is the editor of TS36.411 and TS36.421 of LTE specifications. Research view over the key issue: –Downlink OFDMA Intra-cell Orthogonality High spectra efficiency –Uplink SC-FDMA Promising uplink multiple access scheme with higher terminal Power Amplifier efficiency –Soft frequency reuse suppress the inter-cell interference improve cell edge data rate –MIMO Higher average throughput and spectral efficiency –MBMS on LTE Efficient Broadcast and Multicast transmission on LTE system
10 LTE: Huawei research points Downlink OFDMA –Fast hopping pilot pattern –Multiplexing frequency diversity and Multi-User diversity transmission –AMC process for DL Link Adaptation –PAPR Reduction Uplink SC-FDMA –Distributed pilot design for localized data –HARQ for UL –CQI Report mechanism Inter-cell Interference Mitigation –Soft Frequency Reuse Major frequency with reuse factor greater than 1at cell edge Minor frequency with reuse factor 1 in near Base Station Major frequency bands coordinated with neighboring cells MIMO & Transmit Diversity –MU-MIMO –Combination CDD (Cyclic Delay Diversity) and STTD –MIMO for MBMS
11 LTE: Huawei research points RRC functions –RRC states Location of the Upper RRC and lower RRC RRC terminated in ENB, but some functions such as PDCP control etc. should be in aGW –LTE_Active mobility Handover method: data forwarding and bi-casting or mixed method Handover executing on ENB Should consider power saving mode –LTE_Idle mobility Cell selection and re-selection Mobility handled in aGW –Measurement Measurement gap decided and coordinated by UE and ENB Measurement controlled by ENB (opportunity, control, report, )
12 LTE: Huawei research points MAC functions –Outer ARQ Located in ENB One or more ARQ entities for one UE Outer ARQ operation should be based on segmented/concatenated upper layer PDU Re-segmentation/re-concatenation is supported Adaptive header structure of ARQ PDU and status report should contain segmentation information Status report scheme should be reserved and simplified in LTE Some HARQ and ARQ function could be merged. For example, only one sequence number is used and only one re-ordering function in the receiver. –MAC architecture There is only one MAC entity per cell, UL shared channel and DL shared channel should use joint scheduler. Segmentation/ concatenation should use scheduling information. Async. HARQ may be considered Multiplexing data from different UEs into one block should be avoided More than one Transport Blocks could be transmitted during one TTI