doc 15 17 0598 00 0013 November 2017

doc. : 15 -17 -0598 -00 -0013 November 2017 Generic MAC for Coordinated Topology Date: 2017 -11 -04 Authors: Submission Slide 1 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Abstract This presentation proposes a generic MAC for the coordinated topology in 802. 15. 13 featuring macrodiversity with mobility support between coordinators supervised by a master coordinator. The proposed MAC is suitable for industrial applications which require high link availability and very low latency. Submission Slide 2 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Content n Introduction: OWC for Industrial Wireless n Coordinated topology n Generic MAC for coordinated topology n MAC procedures n How to build MAC frames n Implementation n Removal of DME n What functional split? n Summary Submission Slide 3 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Introduction n Li-Fi: Every light bulb becomes a mobile access point n Li-Fi has challenging cost, energy, form factor n High volumes make it difficult to introduce Li-Fi in general n Introduce intermediate steps n Start with use cases that relax some of these requirements n Promising use cases for Li-Fi n Leverage unique selling points of light compared radio n Mobile backhauling of small radio cells simple P 2 P n OWC for Industrial Wireless n Secure wireless access in conference rooms, class rooms etc. Submission Slide 4 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 OWC for Industrial Wireless • • Industrial OWC: high availability, low latency use MIMO! Use omni-directional Tx at robot and distributed Rxs Build first Li-Fi channel sounder (200 MHz BW, 8 x 8 MIMO) Take 6 x 8 MIMO measurements in real robotics environment Submission Slide 5 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Distributed MIMO Setup • 6 Tx at robots arm pointing to all directions • 8 Rx at the fence of manufacturing cell • 48 channels between all Tx and all Rx measured along mobile robots trajectory • Observations – SNR is low in wide-beam setups – Design may differ from high SNR scenario typical for Li-Fi – Few MHz bandwidth, SC modulation – Diversity-oriented MIMO Submission Slide 6 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Results • MIMO measured along robots trajectory • Fast time variance due to blocked LOS • Spatial diversity creates robust OWC link • High availability reached with macro-diversity concepts • Fit well to ow SNR and moderate data rate requirements Submission Slide 7 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Requirements for Industrial Wireless n High reliability (almost 100% link availability) n spatially distributed OWC frontends n mobile devices with omni-directional beam characteristics n Low latency (< 5 ms) n Conventional handover is too slow for industrial wireless n Move mobility support from network layer into the MAC layer! n Proposal: Use the new coordinated MAC topology in 802. 15. 13 n distributed OWC frontends are considered as coordinators (CO) n Macro-diversity realized with centralized master coordinator (MC) n protocols for distributed multi-user MIMO n suitable functional split between MC and CO inside MAC or PHY Submission Slide 8 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Coordinated Topology n Central control unit: master coordinator (MC) n Distributed access points at fixed locations: coordinators (COs) n Mobile devices with omni-directional characteristics = devices (DEVs) Submission Slide 9 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Generic MAC for coordinated topology n CAPs are only used for network access / joining n High reliability requires contention-free medium access : GTSs in CFP n Connectivity matrix in wavelength-division (WDD) and time-division duplex (TDD) modes WDD: downlink TX RX DEV 1 CO 1 X CO 2 CO 3 X DEV 2 X X DEV 3 X X WDD: uplink TX RX DEV 1 DEV 2 DEV 3 CO 1 X CO 2 X CO 3 TDD: TX CO 1 RX CO 1 X X X CO 3 DEV 1 DEV 2 DEV 3 X CO 2 X X CO 3 X DEV 1 DEV 2 n WDD: VLC is not always reciprocal CO 2 X X X DEV 3 X X X n TDD: Additional direct links between COs and DEVs Submission Slide 10 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Generic MAC functions n Network joining n At any location where the mobile device is situated n TDD with fixed, network-wide split between down- and uplink n CAP for admission / join-request / connectivity estimation n Beacon frame multicell channel estimation feedback in CAP superframe specification n Macro diversity n Multiple COs act as one cluster i. e. transmit or receive jointly n All COs are synchronized e. g. using PTP + Synch. E n Flexible clusters depending on UL/DL connectivity matrix n Data forwarded from/to MC to/from cluster over infrastructure network Submission Slide 11 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Generic MAC frames: Overview n Classical frame structure n Applicable to 802. 15. 13 n Global transmissions e. g. for network access n synchronously transmitted by all COs n Regional transmissions e. g. for macro-diversity n transmitted by individual CO or clusters of COs synchronously n same time slot is reused by distant clusters (disjoint connectivity) n different time slots are used in case of overlaping clusters n Local transmissions e. g. for identification and connectivity estimation n transmitted by individual COs in parallel interference-limited n an appropriate frequency reuse scheme may be implemented here Submission Slide 12 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Global and local frames n Global frames n All COs send the same signal n Needs full synchronization n Local frames n Frames are orthogonal n Use orthogonal resources for adjacent COs n Use non-orthogonal resources for distant COs n Operated in interferencelimited scenario Submission Slide 13 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Regional frames n Used for macro-diversity n All COs in a cluster jointly transmit or receive the same signal on the same resource n Distant clusters (with no connectivity) transmit or receive different signals on the same resources n Overlapping clusters do the same but use different time slots or frequencies to avoid interference Submission Slide 14 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 What frame is local/regional/global? n Beacon frame is global n Allow DEVs to synchronize to the whole network n Contains e. g. mac. OWPANId, MAC address of MC, feedback mode field, reduced superframe spec to advertise CAPs for network access n Medium access frame is typically regional n Transmitted as part of the data in a scheduled cluster n Spatial reuse is supervised by the MC based on connectivity n Multicell channel estimation frame is local n Contains orthogonal sequences to identify adjacent COs n Local information about the specific CO such as MAC address, reuse factor and optional sequence index n Sequences are reused by distant Cos Submission Slide 15 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 What frame is local/regional/global? (2) n Feedback frame is global or regional n As a global frame, FB is used for joining the network • Then it contains connectivity information and is transmitted in CAP • More complex feedback can be provided for scheduling/joint processing (applicable feedback mode is signaled in the beacon frame) n As a regional frame, it is used in a cluster to limit feedback overhead • Simultaneous transmissions take place in distant clusters • In overlapping clusters, transmissions take different time slots Submission Slide 16 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Generic MAC procedures n Beacon transmission n Beacon allows mobile devices to synchronize to the network n Moreover, it informs the device where CAPs are availabe for network access n Information is extracted from global superframe specification Submission Slide 17 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Generic MAC procedures (2) Multicell channel estimation n Enables measuring all channels from all COs n Done by all COs in dedicated resources n Overhead is reduced by spatial reuse n Pulsed Modulation PHY n Code-division multiplex (energy efficincy): different orthogonal code at each CO n Code length, codes+reuse assigned by MC n OFDM PHYs n Frequency-division multiplex: Comb of subcarriers, another comb shift for each CO n Carrier spacing, shift+reuse assigned by MC Submission Slide 18 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Generic MAC procedures (3) n Feedback delivery n Mobile DEVs • Connectivity varies over time n Detected by the device by observing i) the regular beacon frame ii) the multi-cell channel estimation frame n In idle mode, the DEV sends a feedback frame during next CAP. n Before a DEV can start uplink transmission, it has to send a feedback frame, even if downlink connectivity was unchanged. n For continuous transmissions, feedback delivery happens in a CFP. n The feedback packet is fed forward by the CO(s) to the MC. Submission Slide 19 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Generic MAC procedures (4) n Superframe Specification in parallel clusters n MC knows global connectivity and broadcasts global Superframe Spec n Regional Superframe Spec for the cluster is filtered out at the CO n Only the regional SF Specification is forwarded to the DEVs n This allows spatial reuse for both, control information and data Submission Slide 20 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Generic MAC procedures (5) n Superframe Specification in parallel clusters n MC knows global connectivity and broadcasts global Superframe Spec n Regional Superframe Spec for the cluster is filtered out at the CO n Only the regional SF Specification is forwarded to the DEVs n This allows spatial reuse for both, control information and data Submission Slide 21 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Available mechanisms in G. hn/TG 13 D 1 n Many mechanisms can be reused or mobile OWC operation, some t. b. d. n Selected examples G. hn 802. 15. 13 D 1 Centralized scheduling G. 9960 8. 2. 1, 8. 3. 1, coarse time slots only T. b. d. Synchronization Time and frequency; yes, using MAPs, G. 9960 7. 1. 6. 2 Time: yes, beacon periods, 5. 1. 7, Frequency: T. b. d. Random access Yes, CBTXOPs in G. 9961, 8. 6. 1. 2 Yes, in CAP Qo. S and traffic flows Yes: G. 9961, 8. 6. 2 Yes, in CFP Channel Feedback Yes: per user, T. b. d. : per cell Submission Slide 22 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 How to build generic frames n Beacon frame n Global transmission for synch, advertisement of the whole network n Bitwise equal for all COs at a specific time n Contains the assignment of CAPs for network access n Use very robust modulation and coding n Multicell channel estimation frame n Local transmission using orthogonal ressources n HCM can be used as orthogonal codes in Pulsed Modulation PHY n Subcarrier masks can be used in HB OFDM PHY to define comb n Channel between subcarriers in the comb is obtained by interpolation n Channel information can be used for precise localization by triangulation (additional protocol like ranging a. k. a. timing advance) Submission Slide 23 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 How to build generic frames (2) n Feedback frame n Transmitted by OWC DEVs in uplink direction n Using a „general purpose“ MLME frame with new primitive in a reserved GTS which contains management message n Uplink channel estimation can be part of the feedback frame, by adding orthogonal channel estimation sequence n Medium access frame / superframe specification frame n Informs devices about CAPs and GTSs n Contains regional information only, not the global superframe spec. n Transmitted on orthogonal ressource, to avoid interference with other clusters Submission Slide 24 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 How to build generic frames (3) n Macro diversity data frame n Macro diversity = signals transmitted/received by multiple COs („cluster“) n Clusters are preconfigured e. g. by using dedicated VLAN IDs for each cluster and dynamically selected using an appropriate control message protocol n MAC layer has the same data available at all COs: Data is classified and queued at MC and then broadcast to all COs in the cluster via the infrastructure network n Acknowledgements and retransmissions are also processed at the MC n This approach avoids/repairs packet losses during MAC-internal „handover“ high robustness, low latency for industrial wireless Submission Slide 25 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 DME in 802. 15. 7 -2011 n DME in 802. 15. 7 -2011 is used for dimming control n Should be removed in 802. 15. 13 Submission Slide 26 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Coordinator Master Coordinator What functional split in 802. 15. 13? Submission n Optical SAP/PHY switch n Not defined as digital or analog? n Switch is part of PHY and so far controlled by PLME n Should become part of the MAC and (remotely? ) controlled by MC n Concept should be revised in 802. 15. 13, needs more detailled substructure of MAC and PHY n Leverage previous work from Analog n IEEE 1904. 3 Radio over or digital Ethernet (Ro. E) Fronthaul? n IEEE 1914 on Next Generation Fronthaul Interface (NGFI) Slide 27 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Summary n A generic MAC layer is proposed for the coordinated topology. n It is designed for the use of OWC in industrial wireless applications where high availability and low latency are required. n A distributed multiuser MIMO featuring macrodiversity and mobility support inside the MAC has been proposed. n MAC functions have been classified into global, regional and local ones, together with the associated frame structures. n Generic MAC procedures have been highlighted and explained how to build the corresponding frames. n TG 13 needs a clearer view what MAC functions shall be centralized and what distributed, i. e. find a good functional split btw. MC and COs. Submission Slide 28 Volker Jungnickel (Fraunhofer HHI)

doc. : 15 -17 -0598 -00 -0013 November 2017 Possible functional splits NRT-RT split Submission PHY-MAC split Slide 29 Volker Jungnickel (Fraunhofer HHI)