ETSI Project BRAN Hiperlan Type 2 for IEEE 1394 Applications System Overview Source : Jamshid Khun Jush (Ericsson) (THOMSON multimedia) 1
HIPERLAN/2 Standard A new standard developed by the ETSI Project BRAN for wireless access to very high rate IP and multimedia applications Radio sub-system specifications (physical layer, data link layer and convergence layer) Interoperability standard Conformance test specifications Business and Home applications Globally available PHY is aligned with IEEE 802.11a The Basic specification will be ready in 1999 Support of Business functions The Extensions, including 1394 support will be ready in early 2000 Support of Home specific applications 2
HIPERLAN/2 Requirements - 1 Support of IP transporting networks as well as ATM networks Impact on the choice of the length of a protocol data unit (PDU) Capable of supporting QoS based multimedia communications (802.1p, RSVP, ATM, IEEE 1394) Impact on the chosen medium access control (MAC) protocol Control plane is centralised : central controller (or base station) based system User plane is distributed : user data directly flow between devices (peer-to-peer links) Supporting asymmetrical traffic load fluctuating in different connections for different users TDD is an appropriate duplex technique, in particular due to low round trip delay (150 m cell size) 3
HIPERLAN/2 Requirements - 2 Coverage of radio cell @ 25 Mb/s: 15-20 m in typical home indoor environment 30-40 m in a typical office indoor environment 150 m in a large open indoor or typical outdoor environment Capable of handling different interference and propagation situations to provide a communication link at low signal-to-interference ratios to maintain the QoS to trade off between communication range and data rate Link Adaptation with multiple modulation and channel coding schemes Support for multicast and broadcast Low power consumption Power control Power save (sleep mode) 4
HIPERLAN/2 Protocol Stack Wireless Device Bridge Device Application 1394.1 TL 1394.1 TL 1394 H/2 H/2 1394 Control plane User plane Convergence Layer Logical channels Transport channels RLC MAC PHY EC DLC 5
Physical Layer Carrier spacing and sampling rate: 20 MHz Modulation: Coded OFDM (Orthogonal Frequency Division Multiplexing) Handle a large variety of delay spreads => No complex equalizer needed 52 sub-carriers (48 for data, for for pilots) A 64 point FFT Guard intervals: 800 ns mandatory, 400 ns optional Symbol duration 4 µs sub-carrier modulation: BPSK, QPSK, 16QAM, 64QAM (optional) FEC: punctured convolutional code rate 1/2 mother code with constraint length 7, additional rates 3/4 and 9/16 by puncturing 7 physical layer modes with bitrate (Mb/s) 6,9,12,18,27,36,54 6
DLC - Medium Access Control TDMA Dynamic assignment of capacity in uplink, downlink, and directlink - no fixed slot structure Centralized scheduling Could Consider QoS and link adaptation modes Frame structure : BCCH (Broadcast Control CHannel) Broadcasts only the necessary information, e.g. Access point ID (all mobile terminals) FCCH (Frame Control CHannel) Announces the structure of the frame (mobile terminal specific) RACH (Random Access CHannel) Contention based Sloted ALOHA with some priority BCCH FCCH Down-link data Up-link data Direct-link data RACH Air interface frame 2 ms dynamic boundary 7
DLC - Error Control Link Adaptation Code rate and modulation alphabet adaptive to current propagation and interference environments 7 physical layer modes (modulation alphabet and code rate combinations) ARQ Selective repeat Discarding capability efficient for real time applications Short MAC frame allows re-transmission even for voice (2 ms) Forward Error Correction Based on a Reed Solomon at a DLC PDU level Using interleaving Discard corrupted data 8
DLC - Radio Link Control Connection handling Mobility management Setup / release of DLC Association / de-association connections Hand-over Peer-to-peer (ad-hoc) Location update Multicast Radio resource management Security Dynamic frequency selection Authentication Power management Encryption key distribution Sleep mode Alternative security negotiation 9
Convergence Layer Multiple convergence layers One single convergence layer active at a time Mapping between higher layer connections/priorities and DLC connections/priorities Segmentation and re-assembly to / from 48 bytes packets Bandwidth reservation mapping from IEEE 1394 Address/Channel mapping from IEEE 1394 IEEE 1394 Clock Distribution Time stamp processing Self_id emulation ATM UMTS PPP Firewire Ethernet Cell based Packet based 10
Hiperlan 2 Packet based convergence layer IEEE 1394 Service Specific Convergence Sub-layer 11
IEEE 1394 SSCS Architecture 1 Peer to Peer Protocol IEEE P1394.1 Bridge layer Bridge layer Primitives Primitives ETSI BRAN 1394 SSCS Packet based convergence layer - common part DLC PHY layer 1394 SSCS Packet based convergence layer - common part DLC PHY layer IEEE 1394 Service Specific Convergence Sub-layer is one SSCS of the Packet Based Convergence Layers. It uses the services of the CPCS (Common Part Convergence Sub-layer) IEEE 1394 SSCS realizes the mapping between a P1394.1 Transaction layer and the Hiperlan 2 low layers IEEE 1394 SSCS provides virtual bus services to the upper layer : the bridge layer The Bridge layer gathers any bridge relevant mechanism 12
Wireless1394 Device IEEE 1394 SSCS Architecture 2 Wireless 1394.1 Bridge Device 1394 App. 1394.1 Management & Internal Fabric 1394 Tr. 1394.1 Tr. 1394.1 Tr. asynch. Isoch. asynch. Isoch. Isoch. asynch. 1394 CL(SSCS+CPCS) HL2 DLC HL2 Phy 1394 CL(SSCS+CPCS) HL2 DLC HL2 Phy 1394.1 Link 1394.1 Phy Both Bridge aware and non bridge aware wireless devices are considered If non bridge aware, then no 1394 interface outside the device HL2 major interest is to provide 1394 connectivity outside the wireless device Convergence to a bridge layer is fundamental 13
IEEE 1394 SSCS Functions Self id : emulate the self id service on the virtual bus At each device association, the CC allocates a virtual PHY_id, and sends back the list of PHY_ids to all the associated devices Asynchronous transaction address resolution and data transport conversion between bus_id and HL2 MAC_ID setup of DLC Connections between devices for asynchronous transaction data transport Flow control management for request/response independent processing Isochronous channel setup and mapping mapping between a 1394.1 channel and a DLC channel, including the bandwidth reservation Time Stamp processing IEEE 1394 clock synchronization Uses the top frame signal received from the CC 1394 clock is inserted in a DLC connection by a master 1394 clock is read by all the other nodes 14
ETSI BRAN Phase 1 Leaf Bus Bran Portal Phase 1 Virtual Branch Bus Leaf Bus Leaf Bus 2 phases have been identified by the ETSI 1394 CL group Bran phase 1 interconnects a leaf bus to a branch bus Bran portal phase 1 specification shall be stabilized by the end of 1999 Bran portal phase 1 will point to P1394.1 for the features that have been stabilized by the end of 1999 15
ETSI BRAN Phase 2 Leaf Bus Bran Phase 2 Portal Virtual Branch Bus Leaf Bus Leaf Bus Bran portals Phase 2 are backward compatible with Bran Portals phase 1 Bran portals Phase 2 will be compatible to final P1394.1 standard Bran portal Phase 2 schedule to be aligned with final P1394.1 schedule 16
Simple case of leaf bus Leaf / Branch bus allows simplifications in Prime portal selection Bus_id allocation Routing tables (only one bus_id) Network events : only leaf buses allowed to connect to the branch bus We are willing to contribute in the P1394.1 group to work on this simplification 17
Open issues for the Bridge layer Bran phase 1 research & innovation Clock synchronization : net cycle master election Prime portal selection - bus_id allocation Net reset / Net refresh for a leaf bus Issues impacting bridge aware controlers : Device discovery for leaf buses Event mechanism Isochronous channel setup Quanrantine There will be some contributions from Bran supporters in this meeting to solve some of the issues 18