Presentation Title Rethink Fronthaul for UCN PresenterDr. Chih-Lin I SessionSession #6: Strategic Topic #2: 5G Document Name/Version GSC20_Session#6_5G_Chih_IEEE Rev 01 Submission/Revision date: 27 April 2016

Pg 2 | World’s Largest 4G Network ~1.1M 4G BSs BS Terminal Sales volume 210M+ Types 1000+, Price <50$ ~360M 4G Subscribers Subscriber Coverage ~ 330 Feb, 2106 ~1.2B pop (~86%), Reach Villages

Green Communication Research Center established in Oct. 2011, initiated 5G Key Tech R&D. To start a green journey of wireless systems For no more “cells” To make network application/load aware To make BS invisible To enable wireless signal to “dress for the occasion ” To enable Soft RAN via NGFI To enable flexible configuration of diversified access points and optimal baseband function split between BBU pool & RRS Green Soft Super Fast “Towards Green & Soft: A 5G Perspective” IEEE Comm. Mag, Vol.52, Feb G Era: Rethink Fundamentals

Pg 4 | 5G New Requirements Immersive Seamless Tactile Ultra Reliable Massive Ultra Dense New design principles, new key technologies, … Seamless Coverage, Hot Spot High Capacity, Low-power Massive-connection, Low-latency Ultra-reliable

UCN (enabled by C-RAN/NGFI ) High Freq. RIT Low Freq. New RIT Massive-MTC RIT Mission-Critical RIT Low-latency & high-reliability Seamless wide-area coverage Hotspot & high data rate Low-power & massive-connections Green and Soft SDAI (enabled by MCD) LTE evolution Low freq. eMBB NB-IOT Latency redu. V2X PTN PON Transportation network Core Network SDN/NFV RAN E2E 5G System Key Technologies

Pg 6 | User Centric RAN (UCN): C-RAN a key enabler Framework of radio access network Localized data, service & forwarding Multi-Connectivity & Flexible Topology Autonomous Network Unified Access & Seamless Mobility Service Awarenes s CN-RAN Repartition Turbo Charged Edge RAN restructure Network Slice as a Service

Pg 7 | Fronthaul challenges surfaced with C-RAN (2011) Traditional BTS Distributed BTS C-RAN Centralized Control and/or Processing Collaborative Radio Real-Time Cloud Clean System Target Fronthaul used to be an issue for LTE C-RAN: CPRI Compression and WDM CMCC has conducted extensive trials to seek cost- effecitive FH solutions in LTE era Traditional BTS Distributed BTS

Pg 8 | Traditional FH solutions must be revisited in 5G era

Pg 9 | NGFI (xHaul) Traffic dependent Support of statistical multiplexing Support of cell coordination Antenna independent Radio interface technological neutrality The key to achieve FH interface redesign lies in the function re-split b/w BBU and RRU The new NGFI will further lead to re-design of underlined transport networks with packet switching capability

Pg 10 | Decoupling Ant./Non-ant. Related Processing The evaluation of the existing FH Interface (CPRI, OBSAI):  The FH bandwidth is proportional to the number of antennas.  The FH bandwidth is at least 2 orders of magnitude higher than BH bandwidth. Decoupling antenna/non-antenna related processing:  It is proposed that antenna related functions should be moved from the BBU to the RRH.  FH bandwidth will decrease significantly if the BBU/RRH function split can decouple the non-antenna related processing and the antenna related processing. Considering the C-RAN centralized deployment and the technologies of 5G, FH is facing a bandwidth explosion. The number of Carriers in C-RAN The number of antennas FH BW based on the existing FH Interface 10081Tbps Tbps

Pg 11 | Decoupling cell/UE Processing The existing FH interface is a constant bit rate interface, which is load independent and does not match with the features of mobile traffic. Decoupling cell/UE processing:  Cell processing is irrelevant to traffic load and is fixed no matter how many UEs are active.  FH bandwidth will be lower and load dependent.  In C-RAN Mode, cell/UE processing decoupling can further help reduce power consumption. When the traffic load is low, part of C-RAN cloud resource can be shut down. When there is no active UE, BBU software can be switched to a dormant state

Pg 12 | Some symmetrical BBU-RRU function re-split solutions （ Taking LTE as an example ） There are many different aspects between UL and DL:  Generally, the DL rate is not equal to the UL rate.  The bandwidth of UL and DL are not always in the same order of magnitude.  The bit width of UL is usually larger than that of the DL. Decoupling UL/DL processing  NGFI design should take into account the asymmetrical function split solutions.  For example, the function split solution 3 could be used for UL while the solution 4 used for DL. Decoupling UL/DL Processing

Pg 13 | NGFI Progress White Paper on NGFI released in June 2015 Lead of IEEE 1914 (NGFI) WG in IEEE 1 st NGFI WS held & NGFI WP released in June, MoU signing with Broadcom, Intel, Alcatel-Lucent, HuaWei, ZTE, Nokia, Xilinx & Altera Co-founder of IEEE Leading the project of NGFI in CCSA NGFI as the key component in NGMN 5G WP, FuTURE 5G WP NGFI/FH promotion and study in ITU-T, IEEE and 3GPP NGFI Paper in IEEE Communication Magazine & GLOBECOM 2015 NGFI feasibility study with Xilinx “Rethink Fronthaul for Soft RAN”, IEEE Comm. Mag “NGFI, The xHaul”, GLOBECOM 2015

Pg 14 | Challenges Ahead Mapping of FH to Ethernet packet, undergoing in IEEE 1904 WG Stage 1: CPRI encapsulation (applicable to 2G, 3G and 4G) Stage 2: NGFI encapsulation for 5G Latency To meet RT requirement of wireless communication Limited latency budget for FH (e.g. 250us defined in NGMN for LTE C-RAN) Synchronization LTE Frequency sync. of 0.05ppm & phase accuracy of +/-1.5us Higher in 5G Transport of FH packets Over IP, MPLS, etc. E2E QoS O&M, protection etc.

Pg 15 | IEEE NGFI (1914) WG 7 Founding members Target: efficient & scalable FH for 5G Officially approved: Feb Sponsor: IEEE COM/SDB 7 founding companies with more than 50 subscribers so far from ~30 companies Scope of project: - NGFI transport network architecture - Requirements -Function split analysis for LTE The first NGFI WG meeting, April 25-28, San Jose, CA Contact:

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