QoS-enabled Multihop meets High Data Rate

1. QoS-enabled MultihopmeetsHigh Data Rate Oliver Mülhens Philips Research, Aachen (Germany) Contact: oliver.muelhens@philips.com

2. 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

3. Top WNG Requirements (cf. 5GIAG) • High Data Rate (HDR) and scaleability • Mobility: Roaming between subnets • Dynamic QoS management incl. rate, delay, jitter • RF sense: Efficient spectrum usage • Effective range: 100 m LoS, 50 m non-LoS • Usable indoors & outdoors • Automated setup and changes in NW topology • Support for low latency and interactive data • Intelligent power (drain) management • Backward compatibility

4. Top WNG Requirements (cf. 5GIAG) • High Data Rate (HDR) and scaleability • Mobility: Roaming between subnets • Dynamic QoS management incl. rate, delay, jitter • RF sense: Efficient spectrum usage • Effective range: 100 m LoS, 50 m non-LoS • 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 Need 2nd thought

5. Talking about High Data Rate... • The pretty face of HDR • Most prominent requirement of next-gen WLANsand 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 • 802.15.3a: • 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)

6. 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 LoS, 50 m non-LoS)

7. Talking about High Data Rate... • Solution to HDR dilemma: Multihop communication to increase range!

8. Subnet 1 @ frequency 1 CB Subnet 2 @ frequency 2 Multihop Coverage Extension • Inter-subnet communication CB: Cluster Bridge : Control : Data

9. WLAN Evolution • Today: 802.11a WLANs, QoS with 11e ext. • Infrastructure based • Next step: Multihop QoS WLANs • Range extension • Locally centrally-controlled • Infrastructure based • Ultimate goal: Ad-hoc multihop QoS WLANs • Auto configuration • Distributed control

10. 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.

11. Impact of QoS-enabled Multihop (MH) • MH is the first logical step towards the goal to have ad-hoc multihop QoS 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.

12. publicnetwork Example: QoS-enabled In-home Appl. Den Living room • No new wires • Mobility and freedom of device placement

13. Now for the less obvious items...

14. 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

15. publicnetwork Split multi-frequency Forwarding Den Living room • 2 Cluster Bridges that work alternatingly on 2 channels

16. Smart Power Management • Multihop tansmission means • Increased number of transmissions, but… • Due to decreased transmission distances,multihop does not need more power thantraditional single-hop WLANs • Smart power management assigns forwarder functionality primarily to stationary devices • E.g. VCR, TV set or PC in the home

17. T7 T8 T9 T11 T10 T12 T13 T16 T15 T14 Technical Items to be tackled T4 T5 T6 HC1 T3 • Dynamicclustering • Signalling procedures • Membership management • Interconnection of clusters • Forwarding procedure • Choice of forwarding stations • Cluster bridge installation and hand-off • Routing of packets • Type of algorithm • Address resolution • Smooth integration into 802.11 T2 T1 HC2 HC3

18. Conclusions • WNG’s Higher Data Rates lead to decreased coverage range, which has to be compensated for by multihop networking • In the home, QoS-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

19. Next Steps... • QoS-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!

20. MultihopmeetsHigh Data Rate High Data RatemeetsQoS-enabled Multihop means Thank you!