May 2002 doc IEEE 802 11 -02 333

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Qo. S-enabled Multihop meets High Data Rate Oliver Mülhens Philips Research, Aachen (Germany) Contact: oliver. muelhens@philips. com Submission 1 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Outline • • Top WNG Requirements Talking about High Data Rate WLAN Evolution Impact of Multihop Support for low Latency and high Throughput Smart Power Management Conclusions & next Steps Submission 2 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Top WNG Requirements (cf. 5 GIAG) • • • High Data Rate (HDR) and scaleability Mobility: Roaming between subnets Dynamic Qo. S management incl. rate, delay, jitter RF sense: Efficient spectrum usage Effective range: 100 m Lo. S, 50 m non-Lo. S Usable indoors & outdoors Automated setup and changes in NW topology Support for low latency and interactive data Intelligent power (drain) management Backward compatibility Submission 3 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Top WNG Requirements (cf. 5 GIAG) • • • High Data Rate (HDR) and scaleability Mobility: Roaming between subnets Dynamic Qo. S management incl. rate, delay, jitter RF sense: Efficient spectrum usage Effective range: 100 m Lo. S, 50 m non-Lo. S Usable indoors & outdoors Automated setup and changes in NW topology Support for low latency and interactive data Intelligent power (drain) management Backward compatibility Go naturally with Multihop Submission 4 Need 2 nd thought O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Talking about High Data Rate. . . • The pretty face of HDR – Most prominent requirement of next-gen WLANs and WPANs, aiming at high-quality A/V streaming and high-speed computing, is HDR – Striving to achieve hundreds of Mbit/s PHY rate • 802. 11 WNG SC: – 100+ Mbit/s – Range not yet specified • 802. 15. 3 a: – 110 Mbit/s at 10 m – 200 Mbit/s at 4 m – 500 Mbit/s at <<4 m (USB 2. 0 / IEEE 1394 cable replacement) Submission 5 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Talking about High Data Rate. . . • The ugly face of HDR – Alas, TX power is limited • Either by regulations, or • Battery power • Device cost As PHY rates go up, coverage ranges decrease! Wireless networks essentially become pico cells Contrasts effective range requirements (100 m Lo. S, 50 m non-Lo. S) Submission 6 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Talking about High Data Rate. . . • Solution to HDR dilemma: Multihop communication to increase range! Submission 7 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Multihop Coverage Extension • Inter-subnet communication Subnet 1 @ frequency 1 CB CB: Cluster Bridge : Control : Data Submission Subnet 2 @ frequency 2 8 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 WLAN Evolution • Today: 802. 11 a WLANs, Qo. S with 11 e ext. – Infrastructure based • Next step: Multihop Qo. S WLANs – Range extension – Locally centrally-controlled – Infrastructure based • Ultimate goal: Ad-hoc multihop Qo. S WLANs – Auto configuration – Distributed control Submission 9 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Some Facts about Ad-hoc WLANs • • Wireless devices that communicate without necessarily using a pre-existing network infrastructure Self-configuring Terminals can communicate with each other when they are out of range, because some, if not all, nodes are capable of assuming router functionality when needed. The network topology can change constantly because of the movement of the nodes. Submission 10 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Impact of Qo. S-enabled Multihop (MH) • • MH is the first logical step towards the goal to have ad-hoc multihop Qo. S WLANs Beside static coverage extension, MH offers scalability and free node placement – E. g. imagine to include your garden house into your wireless home network. With multihop, it can easily be reached by an automatically assigned forwarding node (FN) in the home. • En passant, with MH the overall system capacity is increased by reducing the average Tx distances. Submission 11 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Example: Qo. S-enabled In-home Appl. Den Living room public network • No new wires • Mobility and freedom of device placement Submission 12 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Now for the less obvious items. . . Submission 13 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Support for low Latency and high Throughput • Latency often seen as a disadvantage of multihop networks – Example: A forwarder switches between 2 channels and transfers data from channel 1 to channel 2 – The shorter the period. . . • … the lower the latency, but • … the higher the overhead (re-synchronize to new channel) Possible solution – Multi-frequency forwarding – Can be split on 2 stations (see next slide) – Maximum throughput will not be halved per hop Submission 14 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Split multi-frequency Forwarding Den Living room public network • 2 Cluster Bridges that work alternatingly on 2 channels Submission 15 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Smart Power Management • Multihop tansmission means – Increased number of transmissions, but… – Due to decreased transmission distances, multihop does not need more power than traditional single-hop WLANs – Smart power management assigns forwarder functionality primarily to stationary devices • E. g. VCR, TV set or PC in the home Submission 16 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 T 4 T 5 T 6 Technical Items to be tackled • T 3 HC 1 – Signalling procedures – Membership management T 2 T 1 T 7 T 8 • HC 2 T 13 HC 3 T 16 • Submission Routing of packets – Type of algorithm – Address resolution T 15 T 14 Interconnection of clusters – Forwarding procedure – Choice of forwarding stations – Cluster bridge installation and hand-off T 9 T 11 T 10 Dynamic clustering • Smooth integration into 802. 11 17 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Conclusions • WNG’s Higher Data Rates lead to decreased coverage range, which has to be compensated for by multihop networking • In the home, Qo. S-enabled multihop WLANs allow for NW scalability, device mobility and freedom of placement • Throughput, latency and battery power issues have been addressed MH goes hand in hand with Higher Data Rate Submission 18 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 Next Steps. . . • Qo. S-enabled Multihop should be on the agenda of the WNG HDR Study Group • Address technical details • Experience from simulation does exist • Prove that multihop fits well into current 802. 11 concepts • Let’s do the first steps of a new WLAN generation! Submission 19 O. Muelhens, Philips Research

May 2002 doc. : IEEE 802. 11 -02/333 r 0 High Data Rate Multihop meets Qo. S-enabled Multihop High Data Rate Thank you! Submission 20 O. Muelhens, Philips Research