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

2. 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

3. 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.

4. 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

5. 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

6. 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

7. 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.

8. 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.

9. 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

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

11. 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

12. 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

13. Prioritized IFS scheme for MANET - IBSS
Example of introducing MCIFS flag in existing MAC format
Frame
Control
Duration ID
Addr 1 2 3
Sequence
control 4
body
FCS
b b3 b 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) ~001110,001011~001111,101000~101111

14. Valid Type and Subtype field

15. 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

16. 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’

17. 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

18. 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

19. 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.

20. 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