5G ar ch it ect ur e Ch al l en ges an d oppor t u n it ies. Icaro Da SEMAFOUR Workshop

Transcription

1 5G ar ch it ect ur e Ch al l en ges an d oppor t u n it ies Icaro Da SEMAFOUR Workshop

2 t h e 5g ar chit ect ur e summar y 1/2 Support of a diverse range of use cases: M-MTC, C-MTC and xmbb High rates (up to 10Gbps), low latency (~1ms) drive a new RAT (NX) RAN Integration of the new RAT (NX) and LTE (5G RAT family) 5G RAN / CN (logical) functional split similar to EPC/LTE Diversity of implementations e.g. co-sited RAN/CN Diversity of deployments e.g. centralized / distributed SDN / NFV to be explored for the CN design Support of network slicing Ericsson Internal Page 2

3 t h e 5g ar chit ect ur e summar y 2/2 Control plane User plane Ericsson Internal Page 3

4 Few wor ds about me Senior Ericsson AB (Wireless Access Networks) Control Plane architecture coordinator in METIS-II (prestandardization for the 5G RAN architecture + CN/RAN split) Co-author of a book chapter about 5G architecture Previously worked with OSS-based SON, SON topics in RAN 3/2, data analytics on e2e protocol traces, network mgmt. prototyping Ericsson Internal Page 4

5 Few wor ds about networ k architecture (R&D context) Most people say that network architecture is about building a system by putting pieces of technology together (bottom up vision) According to network architects (top down vision) Investigation of system requirements / drivers Split functionalities in network elements and define interfaces Design of protocols for interfaces so NE s can communicate Most people ignore that UE s are NE s and the air interface is an interface It s all about standards in order to enable a multi-vendor ecosystem Ericsson Internal Page 5

6 5g ar chit ect ur e Ch al l en ges an d oppor t un it ies #1: New 5G air interface (called here NX): flexible but simple #2: 5G lean design: lean but with efficient access / mobility #3: Integration of NX and LTE evolution: the 5G RAT couple #4: Many use cases, single 5G system: end of one-fits-all? Ericsson Internal Page 6

7 #1: n ew 5G air in t er f ace (NX) f l exibl e but simpl e Support higher frequency bands with wider bandwidth New numerology compared to LTE is required Support lower latency Shorter (and more flexible) TTIs and a new channel structure Better support very dense and EE deployments and beamforming Enabled by for example removing legacy limitations e.g. Cell-specific RS Better support the diverse range of 5G use cases (M-MTC, C-MTC and xmbb) Ericsson Internal Page 7 Ericsson Research Blog, Release 14, the Start of 5G standardization

8 #1: n ew 5G air in t er f ace (NX) flexible but simple Flexibility: potential AI variants per spectrum range, many levels of integration Simplicity: one protocol stack, one new air interface, one set of specifications, common higher layers, common including CN, common network management Ericsson Internal Page 8

9 #2: 5G l ean design l ean but ef f icien t syst em access Industry concensus about the importance of energy efficiency in 5G Minimize always on signals (not directly related to user-data delivery) Sync signals (PSS/SSS), Cell specific-rs (C-RS), Sys info, etc. Currently essential signals for sys access and mobility procedures (common) Today Ultra-lean Reference signals Broadcast system information... No always-on refeference signals Minimum amount of always-broadcast system information... Ericsson Research Blog, Release 14, the Start of 5G standardization, 2015 Ericsson Internal Page 9

10 #2: 5G l ean design lean but efficient mobil it y Challenging propagation in higher frequency drives the usage of massive beamforming Beamforming vs. broadcasting Beam-based system access: how the NW knows where the UE s are? Which signals will the UE monitor? (Less of an issue for small cells) ** lower diffraction and higher outdoor/indoor penetration losses, which means that signals will have less ability to propagate around corners and penetrate walls Beam-based mobility: which signals will the UE measure if C-RSs are minimized? How to achieve reliability? Ericsson Internal Page 10 Ericsson Research Blog, Massive Beamforming in 5G Radio Access, 2015 Barati et al. Directional Cell Search for Millimeter Wave Cellular Systems, 2014

11 #3: Int egr at ion of NX and LTE 5G Ra t c o u pl e, w h y? (1) (2) (3) (4) Higher-frequency spectrum needed to satisfy future traffic demands Joint low-frequency/high-frequence operation needed for full-area coverage Ericsson Internal Page 11 Athley et al, Providing Extreme Mobile Broadband using higher frequency bands, beamforming and Carrier PIMRC 2015

12 #3: Int egr at ion of NX and LTE opt ions f or t he pr ot ocol int egr at ion Common Core Network Common PDCP/RRC Common MAC 5G CN 5G CN 5G CN RRC RRC RRC RRC PDCP PDCP PDCP PDCP RLC RLC RLC RLC RLC MAC MAC MAC MAC MAC PHY LTE PHY New AI 5G RAN PHY LTE PHY New AI 5G RAN PHY PHY LTE New AI 5G RAN Reduced delays on hard HO compared to current interworking Only air interface selection Coordination gains from a common CP: mobility, multi-connectivity, traffic steer. Suitable for any type of backhaul in noncollocated scenarios. Tight coordination gains from crosscarrier scheduling Limited to co-located scenarios or ideal backhaul Ericsson Internal Page 12 Da Silva et al, Tight integration of new 5G air interface and LTE to fulfill 5G VTC Spring 2015

13 #3: Integr ation of NX and LTE nx sleeping st at e Reduction of signaling overhead IDLE CONNECTED is signaling heavy Smartphone connections are very short Between bursts UE moves to IDLE MTC solutions would also benefit from this No RAN context RAN context kept NX should support an efficient sleep mode RAN context is kept (in UE and network) to allow fast and low-overhead transitions Sleep Active Ericsson Internal Page 13 Da Silva et al., Towards an efficient sleeping for 5G devices submitted to Globecom 2015

14 #3: Int egr at ion of NX and LTE nx sl eepin g st at e an d common st at e mach in e Ericsson Internal Page 14 Da Silva et al., Towards an efficient sleeping for 5G devices submitted to Globecom 2015

15 #4: Many use cases, sin gl e 5G syst em en d of one-f its-all? Flexibility: potential variants per service within the same RAN The RAN should support the concept of network slicing (management isolation) Efficient usage of operator s assets such as equipment and spectrum Simplicity was one of the key successes in LTE Future-proofness is a very important requirement for early 5G releases Ericsson Internal Page 15

16 Wh a t a b o u t SON in 5G? New aspects of the 5G architecture drive new self-configuration and selfoptimization challenges Few examples of potential problems for self-configuration/optimization functions Integration of AI variants per carrier frequency Integration of NX and LTE at the RAN level Energy efficiency tuning tradeoff of EE vs. agile system access and mobility CN trends such as NFV/SDN flexibility means headaches to network management Network slicing and QoS observability Ericsson Internal Page 16

17 Request t o t h e n et w or k management communit y Network management understanding is extremely important to bring sanity to the research community working with future network architecture Ericsson Internal Page 17

18 Ericsson Internal Page 18