1. doc.: IEEE 802.11-12-0422r1 SubmissionAlexander Safonov, IITP RASSlide 1 Parameterized QoS for 802.11s mesh networks Date: March 2012 Authors:

2. doc.: IEEE 802.11-12-0422r1 SubmissionAlexander Safonov, IITP RASSlide 2 Objective Parameterized QoS service allows traffic with strict transmission requirements (i.e. end-to-end delay, packet loss ratio constrains) to be accommodated. The service is necessary for transmission of real time multimedia traffic such as VoIP, Video streaming, online gamming etc. In an infrastructure BSS, Parameterized QoS service can be achieved by means of HCCA with TS setup procedure. IEEE 802.11s amendment does not include mechanisms for parameterized QoS provisioning in a mesh BSS. We propose to add more flexibility to the standard to allow designing of parameterized QoS service for mesh networks based on MCCA channel access method.

3. doc.: IEEE 802.11-12-0422r1 SubmissionAlexander Safonov, IITP RASSlide 3 TS setup in mesh BSS (1/2) To provide a flow with Parameterized QoS service in a mesh BSS, channel resources along the path must be reserved based on the flow QoS requirements. We propose to use ADDTS_Request/Response frames ─to propagate per-flow QoS requirements to all relay nodes in the path, i.e. the maximum delay and PLR which shall be achieved ─based on the received QoS requirements of a flow, each relay node in the path uses MCCA to reserve TXOPs for the flow transmission

4. doc.: IEEE 802.11-12-0422r1 SubmissionAlexander Safonov, IITP RASSlide 4 TS setup in mesh BSS (2/2) What shall be changed in the standard? –Allow to use ADDTS_Request/Response frames in a mesh BSS (currently it’s forbidden explicitly) –Add additional fields in ADDTS_Request/Response frames and change processing logic of these frames in a mesh BSS to allow transmitting them along multihop paths –For QoS sensitive flows transmitted by means of MCCA new path selection metric shall be designed in addition to AirTimeLink metric since AirTimeLink metric does not take into account amount of already reserved resources* * Khorov E., Lyakhov A., Safonov A. “Flexibility of routing framework architecture in IEEE 802.11s mesh networks.” // MASS 2011, pp. 777-782, 2011

5. doc.: IEEE 802.11-12-0422r1 SubmissionAlexander Safonov, IITP RASSlide 5 Achieving Parameterized QoS on one hop (1/2) EDCA can not be used to provide Parameterized QoS in a mesh BSS due to the hidden terminals effect We propose to use MCCA as it allows to reserve channel resources in advance (similar to HCCA in an infrastructure BSS) But, in the current standard, MCCA reservations are link based, not flow-based –When an MCCA TXOP (MCCAOP) starts, the MCCAOP owner sets contention parameters to minimum values and chooses the first frame which directed to the MCCAOP responder –The QoS sensitive frame delay depends on the order of packets in the EDCAF queue, therefore delay requirement may appear to be not satisfied –As all packets are kept in EDCAF queues, any QoS sensitive frame can be transmitted via both MCCA and EDCA, therefore PLR requirement may appear to be not satisfied

6. doc.: IEEE 802.11-12-0422r1 SubmissionAlexander Safonov, IITP RASSlide 6 Achieving Parameterized QoS on one hop (2/2) We propose an architecture of flow-based reservations, in contrast to the one of link-based reservations –All QoS sensitive flows shall be transmitted by means of MCCA only –A reservation (or several reservations if retries are needed) shall be established for each particular flow taking into account its specific QoS requirements –In an MCCAOP, frames for which this reservation was established shall be transmitted first What shall be changed in the standard? –Allow to keep QoS sensitive frames not only in EDCAF queues –Change access rules during MCCAOP for MCCAOP owner: during MCCAOP any frame (favoring frames for which this MCCAOP was established) which is directed to MCCAOP responder can be transmitted

7. doc.: IEEE 802.11-12-0422r1 SubmissionAlexander Safonov, IITP RASSlide 7 Enhancement of MCCA protection mechanism (1/2) In the current standard, transmission in MCCAOP is protected according to the following rules : –Neighbors of MCCAOP owner and MCCOP responder can not start EDCA TXOP if it extends across MCCAOP –Neighbors can not establish intersecting MCCAOPs However, these rules are not enough to protect reservations from interference because of ACK- induced and Two-Hop interference problems* Interference can significantly diminish the value of MCCA ACK-induced interference Two-hop interference * A.Krasilov, A.Lyakhov and A.Safonov “Interference, even with MCCA channel access method in IEEE 802.11s mesh networks”, in Proc. MeshTech-2011

8. doc.: IEEE 802.11-12-0422r1 SubmissionAlexander Safonov, IITP RASSlide 8 Enhancement of MCCA protection mechanism (2/2) We propose an adaptive protection mechanism –Each reservation should be protected either in one-hop or two-hop neighborhood from MCCAOP owner and responder depending on the channel conditions –If no-ACK policy is used there is no need to protect MCCAOP owner What shall be changed in the standard? –EDCA rules shall be changed to combat ACK-induced interference –New subfields shall be added in MCCAOP Reservation filed and their proper processing logic: Protection Type indicates whether reservation is protected in one-hop or two-hop neighborhood ACK-policy indicates used in MCCAOP ACK policy TX/RX indicates which station transmits

9. doc.: IEEE 802.11-12-0422r1 Submission 9 NS-3 network simulator 5x5 outdoor grid Traffic –Voice flows (parameters of G.729 codec) –Saturated TCP traffic transmitted by means of EDCA Voice flows transmitted by means of –EDCA (green line) –Standard MCCA (blue line) –Enhanced MCCA with two-hop protection (red line) With enhanced MCCA all established flows are transmitted with acceptable quality even with saturated background traffic Numerical example

10. doc.: IEEE 802.11-12-0422r1 Submission Acknowledgement The proposal was made in the framework of ICT FP7 project FLAVIA Alexander Safonov, IITP RASSlide 10