Collaboration between 2.4/5 and 60 GHz

1. Collaboration between 2.4/5 and 60 GHz Authors: Date: 2010-04-30

2. Abstract • 60 GHz is by itself a promising technology that will provide multi-Gbps throughput at short range. • The inclusion in TGad of fast session transfer feature opens the door to a convergence between all past and future 802.11 technologies and to potential improvements • of each technology, • and of the overall home network. • In [3], we have presented a simple solution for fast session transfer which satisfies one of the potential use cases that can be envisioned. • In this proposal, we remind some additional use cases and propose solutions to them, based on various means of collaboration between 2.4/5 and 60 GHz, including an improved fast session transfer.

3. Use case 1Switch between 2.4, 5 and 60GHz for STA with a switchable interface in STA 5 GHz coverage is available in the whole home, 60 GHz available in rooms Stations with only one bandactive at a given time should perform band selection for all of their flows together - e.g. AP-STB link either in 2.4/5 GHz band or in 60 GHz band Band selection may be based on (a) maintaining coverage with user mobility (b) dynamically changing channel quality (c) load balancing between bands Such use case was largely described in [1] and [2]. A FST solution for single interface devices was proposed in [3]. Slide 3

4. Need to fall back to 60 GHz in case of backhaul saturation WiFi 5GHz ( 500 Mbps) WiFi 60GHz ( 1 Gbps) Use case 1: FST with a switchable interface in STA 5 GHz coverage in the overall home Media server Switchable interface Single link either at 5 or 60 FTTH Set-top box AP Concurrent dual interfaces Slide 4

5. Use case 2Switch between 2.4, 5 and 60GHz for STA with concurrent dual interfaces 5 GHz coverage is available in the whole home, 60 GHz available in rooms Stations with multiple bands active simultaneously at a given time can perform band selection for each of their flows separately E.g. Multiple HD flows between AP and STB either in 2.4/5 GHz band or in 60 GHz band E.g. Session transfer of some HD flows in case of saturation of 2.4/5GHz or 60GHz Band selection may be based on (a) maintaining coverage with user mobility (b) dynamically changing channel quality (c) more efficient load balancing between bands Such use case was largely described in [1] and [2]. A FST solution for multiple interface devices is proposed in the next slides. Slide 5

6. 5 GHz coverage in the overall home, 60 GHz in some rooms Load balancing between bands to improve the throughputs and QoS WiFi 5GHz ( 500 Mbps) WiFi 60GHz ( 1 Gbps) Use case 2: FST with concurrent dual interfaces in STA Media server Concurrent dual interfaces Two links, at 5 and 60 FTTH Flow transfer between interfaces or bonding of the two interfaces Set-top box AP Concurrent dual interfaces Slide 6

7. How to perform the fast session transfer Compared to [3], we consider now that a STA is associated separately on each band/channel, with the physical MAC address of interface of this band/channel. We consider also the creation, both in AP and ST, of a new FST virtual MAC sub-layer, with links to all concurrent interfaces, With one virtual MAC address, which is the only one seen by the network With a forwarding table to link the interface to each flow of a virtual MAC address Data transfer using MAC_virtual FST AP FST virtual MAC Virtual MAC addr: MAC_virtual1 Forwarding decision MAC 60 MAC 5 PHY 60 PHY 5 Association with MAC2 Association with MAC1 PHY 5 PHY 60 MAC 5 Physical MAC addr: MAC1 MAC 60 Physical MAC addr: MAC2 FST virtual MAC Virtual MAC addr: MAC_virtual0 IP FST STA Slide 7

8. How to perform the fast session transfer • The FST virtual MAC is responsible for • The selection of the interface used by a STA or by flows from a STA • Modification of the forwarding table (which should by identical in AP and STA) in case of fast session transfer. • This modification can be done based on different criteria (saturation, link failure), and requires the transmission of signal frames (FST trigger frames in [3]). • A FST negotiation should be performed prior to transmissions. A master and a slave should be defined in this negotiation and the negotiation should lead to the direct acceptance of future switches, to suppress the need to provide a response when a switch is requested. • The forwarding of the packets on the selected interface • By simply reading the forwarding table • The link between virtual MAC addresses in FST virtual MAC sub-layer and physical MAC addresses in interface MAC sub-layers. Slide 8

9. How to perform the fast session transfer • With such an architecture, it is possible to • Perform fast session transfer for all flows of a STA • Only one active interface for power savings, coverage issues or interference reductions • Perform fast session transfer for only some flows of a STA • Better granularity for load balancing algorithms • Perform a bonding of all interfaces • Aggregation of the throughput of all interfaces • In this case, additional functions must be added to the FST virtual MAC Slide 9

10. Use case 32.4/5GHz Assisted 60GHz May 2010 The use of 2.4/5GHz management to discover, assist training, and schedule 60GHz transmission is a solution to improve the performance of 802.11ad at larger range 60G Link assisted by 2.4/5G Media server Wifi 60GHz ( 1 Gbps) Wifi 5GHz ( 500 Mbps) AP Slide 10 Slide 10

11. Beamforming would be the key technology to enhance 60GHz range However, beamforming could only be functional after discovery and training of the target device If 802.11a/b/g/n can coincide with 802.11ad, they can be used to better facilitate 60GHz beamforming March 2010 2.4/5GHz Assisted 60GHz - Overview Slide 11

12. Several ways to effectively use 2.4/5GHz frames to assist 60GHz operation were previously proposed in [4] 2.4/5GHz Beaconing Provide 60GHz service discovery, especially when STAs are out of 60GHz omni range Share 60GHz Beacon Offset (i.e. TX timing) so STAs can discover when to update beamform information or retrain if necessary. Provide 60GHz Scheduling Information that can be used to adjust the RX/TX beam-pattern to the intended receiver/transmitter 2.4/5GHz Management Frames assisted 60GHz scheduling Can facilitate better 60 GHz operation via some frames (e.g. Re-scheduling Frame) Communicate with all STAs in the BSS via 2.4/5GHz frames; single STA via 60GHz 2.4/5GHz Management Frames assisted 60GHz training Aid between STAs whose 60GHz training information is not available or too aged Use frames to initiate 60GHz training procedure 2.4/5GHz Assisted 60GHz - Options Slide 12

13. It will not be possible to cover entire home with a single 60GHz network 60 GHz should beused to provide intra-room ultra-fast connections.  In room 60 GHz improves the link reliability and the link robustness in the presence of interferences 2.4/5 GHz should be used to provide inter-room connections 2.4/5 GHz should be used as well as intra-room connections in case of mobility where a 60GHz link would not be maintained Use case 4Backhaul at 2.4/5GHz, in-room 60GHz Slide 13

14. WiFi 5GHz ( 500 Mbps) WiFi 60GHz ( 1 Gbps) Use case 4Backhaul at 2.4/5GHz, in-room 60GHz Media server 60G P2P setup with 2.4/5G AP Slide 14

15. Simple extension of TDLS 2.4/5 GHz manages setup procedure, and 60 GHz provides a multi-Gbps direct link Discovering TDLS capable STAs in the same BSS is easy because 2.4/5 GHz has a wider and omni directional range AP 2.4/5G 60G DLS setup request DLS setup response STA2 STA1 Direct link 2.4/5GHz DLS of 60GHz P2P Slide 15

16. Device discovery and beamforming training could be started with 2.4/5GHz signaling. 2.4/5GHz 2.4/5GHz 2.4/5GHz 60GHz 60GHz 60GHz Setup signal flow of 60GHz P2P DLS setup response DLS setup request AP Waiting for Response 60GHz Training Frame Beamformed Data STA1 DLS setup request STA2 DLS setup response Waiting for Training Frame 60GHz Training Feedback Slide 16

17. Collaboration between the 2.4/5 and 60 GHz bands would enable user expectations for 802.11ad to be met Fast session transfer seamlessly provides both the wide coverage of WLAN and the very high throughput of 60 GHz when available FST can improve the home network by allowing joint management of multiple bands (2.4/5 and 60GHz) 2.4/5 GHz assisted 60 GHz enhances the 60 GHz range by improving discovery and assisting training and scheduling of 60 GHz transmission 2.4/5 assisted DLS of 60 GHz permits 60 GHz to be used for in-room ultra-fast connections while 2.4/5 provides inter-room connections and manages 60 GHz links We believe that these solutions would improve the overall home network Conclusions May 2010 Slide 17 Slide 17

18. Straw polls May 2010 • Do you support inclusion of Fast Session Transfer, as described in 10/492r0 in the TGad draft amendment? • Yes: , No: , Abstain: • Do you support inclusion of 2.4/5 GHz assisted 60 GHz, as described in 10/492r0 in the TGad draft amendment? • Yes: , No: , Abstain: • Do you support inclusion of 2.4/5 assisted DLS of 60 GHz, as described in 10/492r0 in the TGad draft amendment? • Yes: , No: , Abstain: Slide 18

19. [1] J. Benko et al, “5-60 GHz use cases”, 802/11-09-0835r0 [2] L. Cariou et al, “Fast Session Transfer use cases”, 802/11-10-0134r0 [3] L. Cariou et al, “Fast Session Transfer”, 802/11-10-0491r0 [4] Y. Morioka et al, “802.11ad New Technique Proposal”, 802/11-10-0259r2 Reference