<author>, <company> <month year> September 2018 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: IEEE P802.15.13 – MAC layer support for multiple optical frontends Date Submitted: 10 Sep. 2018 Source: Kai Lennert Bober, Volker Jungnickel [Fraunhofer HHI] Address: Einsteinufer 37, 10587 Berlin, Germany Voice:[+49-30-31002 302], E-Mail:[kai.lennert.bober@hhi.fraunhofer.de] Voice:[+49-30-31002 768], E-Mail:[volker.jungnickel@hhi.fraunhofer.de] Re: Abstract: Purpose: Contribution to IEEE 802.15.13 Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15. Kai Lennert Bober, HHI <author>, <company>

IEEE P802.15.13 MAC Layer support for Multiple Optical Frontends <month year> September 2018 IEEE P802.15.13 MAC Layer support for Multiple Optical Frontends Date: 2018-09-10 Place: Waikoloa, Hawaii Authors: Kai Lennert Bober, HHI <author>, <company>

September 2018 Content This doc. contains a proposal for protocol procedures and frame types, necessary to support distributed optical frontends and MIMO techniques in the star topology. Kai Lennert Bober, HHI

Targets of the Distributed Optical Frontend (OFE) Approach September 2018 Targets of the Distributed Optical Frontend (OFE) Approach Introduction of spatial diversity on the signal level Enable spatial reuse with smooth handover performance and high QoS Low level “soft handover”: OFE form virtual cells following the device’s movement, fully transparent to the network layer Coordinator Fronthaul Optical Frontend Device OWC signal Fig 1: Coordinator in star topology with distributed OFEs serving two devices simultaneously Kai Lennert Bober, HHI

Fronthaul Technologies and Functional Split September 2018 Fronthaul Technologies and Functional Split The coordinator’s PHY is connected with the its OFEs via fronthaul The implementation of the fronthaul is out of scope. Analog fronthaul could be plain coax cable, or fiber transport of analog signals Digital fronthaul could be transport of digitized waveform samples (CPRI) A splitting of signal chain functionality, as also discussed as “new functional splits” in mobile networks can be facilitated Digital fronthaul transport technologies are currently being investigated in the context of mobile networks and requirements are being defined in different standardization activities: eCPRI IEEE 802.1CM … Kai Lennert Bober, HHI

September 2018 Fronthaul Delay Fronthaul virtually increases propagation delay. Order is up to ~100 µs. Fronthaul delay tF must be known and approximately the same for all OFEs. Remaining delay differences between air times at different OFEs must be very small, i.e. well below ½ cyclic prefix duration. tF Downlink transmission tP Kai Lennert Bober, HHI

PHY Support of Multiple OFEs September 2018 PHY Support of Multiple OFEs PHY of the coordinator has multiple transmit- and receive chains (TRX chains) and multiple ports for OFEs (OFE-Ports). Fronthaul is transparently included in logical PHY by the implementer TX for each PSDU via PD-SAP On which OFEs to transmit Delay difference compensation per OFE (in opt. clock cycles). RX configuration through PLME-SAP Groups of OFEs in virtual cells for combining in uplink PD-SAP PLME-SAP PHY … TRX OFE- Ports PHY with multiple TRX chains and OFE-Ports Kai Lennert Bober, HHI

September 2018 Superframe Structure for Spatial Reuse and Joint Transmission + Reception BP CAP CFP Slotted uplink random access without carrier sensing in CAP. For association and reconnection only; collisions may occur. GTS allocations per device for regular transmission and reception in the CFP. Different GTS allocated in same superframe slot but different OFE slots (SDMA). GTS spans over multiple OFE slots, implying a “virtual cell” for joint transmission / reception. Receive A OFE slots Receive B Receive C Receive D Superframe slots GTS Concept of superframe structure. Only receive direction is considered for simplicity. A,B,C,D = devices. Kai Lennert Bober, HHI

September 2018 Dynamic GTS If the same superframe slots are “reused” in GTSs of different devices (spatial multiplex), mobility can lead to frame collisions when devices with those GTSs approach each other. Hence, the GTS allocations must be rapidly adapted to mobility. Keep existing semi-static GTS allocation mechanism via management frames (5.1.10 and Appendix G in D3). Proposal: So called dynamic GTSs can be assigned to devices by the coordinator via control frames, in addition to the semi-static GTS allocations. Dynamic GTS are only valid for a specified number of superframes and shall not be used thereafter. Semi-static GTSs are still valid unless deallocated via the mgmt. protocol. Kai Lennert Bober, HHI

Dynamic GTS Descriptor September 2018 Dynamic GTS Descriptor Dynamic GTS descriptors are transmitted via control frames. The dynamic GTS descriptor is similar to the semi-static GTS descriptor but has no device address and contains and Validity field. Validity field in dynamic GTS descriptor may contain the number of subsequent superframes for which a dynamic GTS is assigned. The other fields are the same as in subclause G.2.1.6 Bits: 0-15 16-19 20-23 Device Short Address GTS Starting Slot GTS Length Bits: 0-3 4-7 8-15 GTS Starting Slot GTS Length Validity Semi-static GTS descriptor Dynamic GTS descriptor Kai Lennert Bober, HHI

Association and Reconnection September 2018 Association and Reconnection New devices or devices that lost the connection and do not have GTSs allocated can transmit association requests and reconnection feedback frames in the CAP. Proposal: CAP transmission: Slotted Aloha in macro slots which contain multiple superframe slots, which can hold a whole frame each. Proposal: Estimated downlink CSI is included in random access frame. channel est. BP CAP CFP CO association / reconnection + feedback beacon: multi cell pilots DEV macro slot Multi-cell channel est. control frame Kai Lennert Bober, HHI

Channel Estimation, CSI Feedback and GTS Update September 2018 Channel Estimation, CSI Feedback and GTS Update Channel estimation is based on multi-cell pilots in the beacon. CSI feedback is transmitted regularly via control frames in GTSs. The coordinator updates the GTS allocations dynamically based on CSI feedback. Dynamic GTSs are updated via control frames and valid during next superframe, if validity=0, otherwise for multiple superframes. Previous dynamic GTS allocations lose validity. GTS update is acknowledged in next feedback frame. channel est. BP CAP CFP CO beacon: multi cell pilots feedback GTS update DEV control frame Multi-cell channel est. channel est. Kai Lennert Bober, HHI

September 2018 Backup slides Kai Lennert Bober, HHI

Device Address Present September 2018 GTS Descriptor List Multiple GTS descriptors are contained by the GTS descriptor list field. GTS Descriptor Count is the number of contained GTS descriptors Validity Present indicates whether the GTS descriptors have validity fields, i.e. describe dynamic GTSs Device Address Present indicates whether all descriptors have an Device Address field or the device address is deducted from the corresponding control frame destination address GTS directions contains a bitmap that describes the corresponding GTSs direction (X = transmit, Y = receive) GTS Descriptors contains the descriptors Bits: 0-7 8 9 10-15 variable GTS Descriptor Count Validity Present Device Address Present reserved GTS Directions GTS Descriptors GTS descriptor list field Kai Lennert Bober, HHI

Data and Management Transmission September 2018 Data and Management Transmission Data and management frames are transmitted in the corresponding GTSs. Due to the separation of uplink and downlink, as well as the potentially large delay introduced by the fronthaul, delayed- or block acknowledgment is used. Acknowledgment information is transmitted in control frames. BP CAP CFP CU data + management data + management MU Kai Lennert Bober, HHI

Transmission by Devices September 2018 Transmission by Devices Devices are only allowed to transmit if they received the beacon frame in the corresponding superframe (as currently in the draft). Non-synchronous „blind“ transmission is thereby ruled out. Upon recovered beacon reception after beacon tracking loss, feedback is transmitted again in known GTSs or in the CAP if no GTS allocation is present. Kai Lennert Bober, HHI

Scheduling of (Dynamic) GTS September 2018 Scheduling of (Dynamic) GTS The details of GTS allocation are left to the implementer‘s discretion. Implementers can differentiate themselves through proprietary scheduling algorithms. For regular control exchange, each device must have at least a single GTS allocated periodically. TDD operation: The coordinator/scheduler can separate uplink and downlink network-wide through corresponding clever allocation of the uplink- and downlink GTSs. Support of low delays and cycle times for industrial traffic: If every device can have at most a single GTS allocated in each superframe, packets to be transmitted can experience a long queueing delay if the superframe is long and the GTS is valid only in a small portion of the superframe. To prevent large queueing delays it should be possible to allocate multiple GTSs per device for each downlink and uplink respectively in each superframe. Kai Lennert Bober, HHI

Affected MAC Frames Beacon frame CSI Feedback control frame September 2018 Affected MAC Frames Beacon frame CSI Feedback control frame Block Acknowledgment control frame GTS Update control frame Association request management frame Kai Lennert Bober, HHI