Prioritized MAC Access Mechanism of Routing-related Frame for ESS Mesh SK Sung, Samsung Electronics s.sung@samsung.com Hello everyone. I’m SK Sung and now working for Samsung Elec.

Overview Introduction Requirement and recommendation for Mesh NW An open problem on QoS Mesh QoS Example: A prioritized MAC access mechanism of routing-related frames for mobile ad hoc network Independent BSS case ESS Mesh case Conclusion Conor/Tyan Shou Jou

Motivation Samsung is basically supportive for the ESS mesh network standardization efforts. We recommend an enhanced quality of service in mesh networking by adopting efficient channel access scheme, which considers specific features of protocol frame.

Introduction ESS Mesh, a broad chance of mobile application Interactive ad hoc gaming, chatting,…. Instant messaging (ex. PoW) Car-oriented application (emergency propagation) QoS Requirements of mobile ad hoc Mesh NW Throughput Latency Security Reliability 서명환/마중수

Introduction Factors affecting on the latency in ESS Mesh network Routing algorithm Channel access mechanism Location of routing protocol and more… Workscope of ESS mesh PAR covers MAC amendment/extension, which can render efficient channel access possible But among these, the most proper factors that can be treated in the ESS Mesh is channel access mechanism

Advantage of prioritized routing access Prioritized channel access for routing-related frame Configure fast and efficient ad hoc routing path Potentially reduce packet loss via fast link setup IP MARP Core MAC PHY Application B C MARP: Mobile Ad hoc Routing Protocol

802.11 MAC 802.11 MAC access mechanism Contention-based and contention free strategy For infrastructure BSS, AP, as PC, is generally vested with the control of coordination functions Discriminatory IFS according to PCF/DCF Prioritized access to medium through PCF For independent BSS case, all the STAs will basically have equal chance of channel access using DIFS, though have random backoff procedure.

Open Issues? To obtain fast channel access for automatic topology learning and dynamic path configuration, whether SG MES will take complete adoption of QoS-enhanced features from 11e, or simply make minor amendment reflecting ESS mesh-specific requirement from the current MAC Features of 11e draft, Enhanced channel access using EDCA/HCCA HCF reflecting UP Hybrid and complicated entity/function for QoS Here we come into an open issue to decide. The problem is~ Considering these features, we are again confronted with the open question. But my recommendation is that we’d better make use of a simple version to enhance QoS.

Conclusion We suggest QoS based MAC Access Scheme for ESS mesh Prioritized medium access mechanism for routing-related frame The MAC amendment be independent on the information that in which layer the ad hoc routing protocol exists, but recommended to be placed at lower layers(L3 or L2.5) considering latency

Back Up Examples of Prioritized Access for routing related frame IBSS Ad hoc WDS

Prioritized IFS scheme for MANET - IBSS Independent BSS(IBSS) Prioritized medium access using shorter IFS SIFS< MCIFS (MARP control IFS) < DIFS Guaranteed access priority than ‘Random Backoff Time’ DIFS Next Frame Defer Access SIFS MCIFS (control frame) (data frame) Busy Medium Backoff Window Slot time Contention Window Select slot and decrement backoff as long as medium is idle No functional entity playing as PC Backoff procedure after DIFS Network Access Method for IBSS

Prioritized IFS scheme for MANET - IBSS Access and backoff procedure Data Frame Station A DIFS Defer Defer Station B MANET data frame MCIFS Defer Station C MANET control frame DIFS DIFS Defer Defer Station D MANET data frame Backoff procedure for IBSS

Prioritized IFS scheme for MANET - IBSS Example of introducing MCIFS flag in existing 802.11 MAC format Frame Control Duration ID Addr 1 2 3 Sequence control 4 body FCS b2 b3 b4 b7 Protocol Ver. Type Subtype To DS From More Frag Retry PWR Mgt data WEP Order The reserved bits in this field can be used whether the incoming frame is MANET control frame or MANET data frame e.g) 000110~001110,001011~001111,101000~101111

Valid Type and Subtype field

Ad hoc WDS Hosting AP functions in ad hoc WDS Inherit general AP functions Constructs/Reconfigure ad hoc DS Construction of wireless backbone network Recommended to provide prioritized access to DCF/PCF at BSS AP#n Internet AP#2 Router AP#4 802.3D LAN AP#1 Bridge AP#3

Prioritized IFS scheme for MANET - ad hoc WDS Ad hoc DS formation scheme prior to normal access mechanism Prioritized medium access using shorter IFS Ex.1) SIFS< MCIFS = PIFS < DIFS Ex.2) SIFS< MCIFS < PIFS < DIFS Guaranteed access priority than ‘Random Backoff Time’

Prioritized IFS scheme for MANET - ad hoc WDS Example 2 SIFS< MCIFS < PIFS DIFS (data frame) Contention Window PIFS (data frame) Slot time DIFS MCIFS (control frame) Busy Medium SIFS Backoff Window Next Frame Select slot and decrement backoff as long as medium is idle Defer Access Network Access Method for adhoc WDS

Pros and cons Pros MANET route can be constructed relatively fast due to less contention when accessing medium Mitigates data loss due to delayed MANET routing construction Possibly, allows faster node mobility Cons Required is algorithm/equipment to decide whether incoming frame is MANET control or data frame

Introduction Mobile Ad hoc Network (MANET) MANET examples with regard to WLAN Independent BSS, ad hoc WDS MANET routing algorithm generally discovers dynamic topologies and configures path using link metric information Each node has a self-configuring and healing functionality When initiating MANET routing algorithm, the exchange of routing-related frame is recommended to have priority to other data traffic frame.

Adhoc Routing Protocol MANET frame and stack MANET control frame Information for routing algorithm PHY aware metric Routing path MANET data frame Lower layer data unit Application IP 생략 MARP Core MAC PHY