1. Enterprise extensions - overview
April 2007
doc.: IEEE /0570r0
Apr 2011
Enterprise extensions - overview
Date:
Authors:
Brian Hart, Cisco Systems
Brian Hart, Cisco Systems

2. Outline Problem statement Overview of Proposed Solution Details
Apr 2011
Outline
Problem statement
Overview of Proposed Solution
Details
The Centralized Coordination Service Set and the Extended Centralized PCP/AP Cluster
Summary of Control mechanisms
Interference reporting in an ECPAC
Summary of Benefits
Step-through normative text in 11/533
Brian Hart, Cisco Systems

3. Problem statement: Dense 60GHz devices in open environments
Apr 2011
Problem statement: Dense 60GHz devices in open environments
In OBSS, a TXSS such as within the BTI, A-BFT or DTT is a directional jammer
A badly behaved transmission in a dense environment
In OBSS, a pseudo-static SP without CCA (or NAV) is a simple jammer
Enterprise use cases are presently not well addressed, such as:
“sea” of open desks
“sea” of cubes with embedded offices
open lecture theaters
etc
Brian Hart, Cisco Systems

4. Overview of Proposed Solution
Apr 2011
Overview of Proposed Solution
TXSS overlap is avoided by centralized synchronization of “wired/2.4/5GHz” APs (S-APs) then scheduling their BIHs so they do not overlap
Via out of scope mechanism
Use a modified clustering mechanism to extend this behavior to BSSs in the neighborhood and/or passing through
Neighboring PCP/APs that don’t hear a S-AP aren’t required to do anything (areas experiencing density issues need to carpet the area with S-APs)
Neighboring PCP/APs that do hear a S-AP must cluster or go to the guaranteed reserved channel(s) (advertised via 11v Channel Usage) not subject to these clustering requirements
Via a modified clustering that involves association from one STA in a MA-STA PCP/AP to the S-AP
Each S-AP indicates which cluster time offsets are free
Respecting other BSSs’ BTI, A-BFT & AT can be mandated
Performing all DTT TXSSs within a universal pseudo-static SP can also be mandated
Protected Periods can be mandated for the DTT
Interference reporting is extended suitably
Involves a non-backwards-compatible change to Cluster Report element
Brian Hart, Cisco Systems

5. Apr 2011
The Centralized Coordination Service Set and the Extended Centralized PCP/AP Service Set
Centralized Coordination Service Root synchronizes and configures “wired” APs = S-APs
The Centralized Coordination Service Root + S-APs = Centralized Coordination Service Set (CCSS)
Nearby PCP/APs cluster to these S-APs
New cluster type, called “Centralized PCP/AP cluster”
The CCSS + clustered PCP/APs, plus clients = Extended Centralized PCP/AP Cluster (ECPAC)
New
Modified
Brian Hart, Cisco Systems

6. The Beacon Interval Header and TXSS CBP
Apr 2011
The Beacon Interval Header and TXSS CBP
The Beacon Interval Header (BIH, = BTI, A-BFT and AT) is confined to Beacon SPs
TXSSs are confined to the TXSS CBP, which is a regular allocation across the ECPAC
i.e. the “badly-behaved” communication modes are confined to the Beacon SP and TXSS CBP
S-APs are assigned non-overlapping Cluster Time Offsets by the Coordination Service Root
BTI
A-BFT AT
DTT
Nearby PCPs and APs are advised of free Cluster Time Offsets by their S-AP
Beacon SPs prevent contention during BIHs
Any STA can use a TXSS CBP for TXSSing (or sending data)
TXSS CBP
TXSS CBP
TXSS CBP
BIH
DTT
Beacon SP
DTT
Beacon SP
DTT
BIH
DTT
S-AP1
TXSS CBP
TXSS CBP
TXSS CBP
TXSS CBP
TXSS CBP
TXSS CBP
TXSS CBP
TXSS CBP
TXSS CBP
TXSS CBP
TXSS CBP
TXSS CBP
Out of range
Beacon SP
BIH
Beacon SP
Beacon SP
S-AP2
Clustered
Beacon SP
Beacon SP
BIH
Beacon SP
AP3
BIH
Beacon SP
Beacon SP
BIH
PCP4
Beacon Interval
Brian Hart, Cisco Systems

7. Summary of Control Mechanisms
Apr 2011
Summary of Control Mechanisms
When in range of an S-AP within an CCSS, a PCP/AP shall either join the S-AP’s Centralized PCP/AP cluster or go to a free channel
As advertised by the S-AP via v’s Channel Usage procedures
A PCP/AP shall select an unused Cluster Time Offset if one is advertized by its S-AP
If mandated by an S-AP, a PCP/AP shall respect the BIH
Complete its own BTI, A-BFT and AT within the Beacon SP Duration
Reserve Beacon SPs for Cluster Time Offsets in use
If mandated by an S-AP (and potentially echoed via a PCP/AP), STAs shall respect the TXSS CBP
Complete any TXSSs within the TXSS CBP
If mandated by an S-AP (and potentially echoed via a PCP/AP), STAs shall use Protected Periods for their SPs
BIH Enforced
TXSS CBP Enforced
Protected Period Enforced
Reserved
Bits: 1 5
ECPAC Policy Detail field
Brian Hart, Cisco Systems

8. Interference reporting in an ECPAC
Apr 2011
Interference reporting in an ECPAC
DBand Beacons are reported from client to PCP/AP to S-AP to Centralized Coordination Service Root
To avoid the “Beacon of Death” problem, a PCP/AP with only one antenna and one sector must jitter the timing of its DBand beacon
Cluster Report element is changed in a non-backwards compatible way (TSCONST should be an element)
Key
Beacon causes interference
Cluster Report (different ECPAC Cluster or same Cluster Time Offset)
Brian Hart, Cisco Systems

9. Sample Simulation Results: ClusterMaxMem=32
Apr 2011
Sample Simulation Results: ClusterMaxMem=32
TXSS impact on decentralized Data
Beacon difference with centralized
Beacon difference with centralized, even without TXSS
Data CINR:
No OBSS TXSSing: Centralized-clustering and Decentralized-clustering are similar (PP not modeled)
During OBSS TXSSing
Decentralized-clustering: average CINR is reduced by 12 dB due to TXSS
Centralized-clustering: No impact
Beacon:
No OBSS TXSSing
Centralized-clustering: no issue
Decentralized-clustering: 15%~20% STAs may have an issue receiving the beacon, since CINR is less than 7 dB (3dB sensitivity + 2stddev lognormal shadowing)
Beacon CINR in Centralized-clustering is about 15 dB higher than that in Decentralized-clustering
Decentralized clustering: CINR drops by 4 dB
Centralized clustering: without impact
Scenario
# S-AP/AP/PCP are impacted by opening the door
Decentralized-clustering 9
Centralized-clustering 1
Brian Hart, Cisco Systems

10. Summary of Benefits Apr 2011
On selected channels within an isolated space, complete avoidance of directional jamming from OBSS DBand Beacons in BTI and Sector Sweeping in A-BFT
More Cluster Time Offset indices prevents PCP/AP lockout
15-20% of clients reduced to ~0% of clients that can’t receive their beacons
Ditto for TXSSing within DTT (10 dB CINR recovered)
SPs are prevented from creating uncontrolled directional interferers
Still 1-hop maximum wireless clustering only
Since the requirements from large scale field trials requirements are not fully known yet, these mitigation measures can be selectively enabled where found necessary
Devices not supporting Centralized clustering are guaranteed their own channel(s) to use
See backup slides for simulation study
Brian Hart, Cisco Systems

11. Apr 2011
Simulation Study
Performance comparisons between Centralized-clustering and Decentralized-clustering in an enterprise environment
Note: For many overlapped environments, Centralized clustering may involve more complexity/performance than required. A DS or a Coordination Service Root may not be available. For these use cases, channel selection and/or Decentralized clustering remains the best choice.
Brian Hart, Cisco Systems

12. Simulation Environment and Setup
Apr 2011
Simulation Environment and Setup
16x16=256 cubicles
Area size= 44.8 x 48 meters
32 APs: set on the ceiling, height: 3m
One STA and one PCP in each cubicle, with height 1 meter
Conference room: one AP , 8 STAs
AP/PCP: 32 antennas
STA: (50%,50%) 32, 4 antennas
Channels: 11 ad models
AP to AP: LOS, 1.5dB lognormal
AP/PCP/STA: NLOS
Conference room to cubicles: additional 2dB lognormal
ClusterMaxMem: 8/16/32
Multiple directional Beacon: 32
Simulation realizations: 3000
2db
Brian Hart, Cisco Systems

13. Apr 2011
What is Simulated
The Decentralized/Centralized-Clustering generating procedures
Decentralized/Centralized-Clustering maintenance
Comparisons of CINR coverage between Decentralized-Clustering and Centralized-Clustering
Impact of the conference room door open/close on Decentralized- Clustering and Centralized-Clustering:
Number of S-APs, APs and PCP in the Decentralized/Centralized-clustering need to update their cluster-roles or change their Beacon offset is provided.
Brian Hart, Cisco Systems

14. Summary of Simulation Results
Apr 2011
Summary of Simulation Results
Beacon
Without TXSS
Decentralized-Clustering
10%~20% area has issues receiving the Beacon, where the Beacon CINR is less than 7 dB (3dB due to -78dBm RSSI/noise floor + 2 sigma of log-norm gives 4 dB)
Sensitive to environment change: multiple co-channel APs may need to update their cluster role, change their Beacon offset or change their channel when open/close the door of conference room
Centralized-Clustering
There is no issue to receive Beacon with a larger ClusterMaxMem
Robust to the environment change
With TXSS
Decentralized-clustering: about 4 dB CINR degradation compared to without TXSS
Centralized-clustering: without impact from TXSS
Data CINR
CINR of Centralized-Cluster and Decentralized-Cluster are similar
Decentralized-clustering: big impact from TXSS, 12 dB CINR is reduced
Brian Hart, Cisco Systems

15. Summary of Simulation Results
Apr 2011
Summary of Simulation Results
Decentralized Cluster
Centralized Cluster
Beacon
No TXSS
10%-20% area has no coverage.
Sensitive to door opening
No issue on coverage
Robust to door opening
TXSS
About 4 dB CINR degradation from No TXSS case
No impact from TXSS
Data
Distribution of CINR is similar to Centralized cluster
Distribution of CINR is similar to Decentralized cluster
About 12 dB CINR degradation from No TXSS case
Brian Hart, Cisco Systems

16. Simulation Results: ClusterMaxMem=8
Apr 2011
Simulation Results: ClusterMaxMem=8
Data CINR:
Without TXSS: Centralized-clustering and Decentralized-clustering are similar
With TXSS:
Decentralized-clustering: average 12 dB CINR is reduced due to TXSS
Centralized-clustering: No impact
Beacon:
Without TXSS:
Centralized-clustering: no issue
Decentralized-clustering: 10%~20% STAs have issue to receive Beacon, where CINR less than 7 dB
Beacon CINR in Centralized-clustering is about 7 dB higher than that in Decentralized-clustering
With TXSS
Decentralized-clustering: CINR drop 4 dB
Centralized-clustering: without impact
TXSS impact on decentralized Data
Beacon difference with centralized
Beacon difference with centralized, even without TXSS
Scenario
# S-AP/AP/PCP are impacted by open the door
Decentralized-clustering
5.3
Centralized-clustering 1
Brian Hart, Cisco Systems

17. Simulation Results: ClusterMaxMem=16
Apr 2011
Simulation Results: ClusterMaxMem=16
TXSS impact on decentralized Data
Beacon difference with centralized
Beacon difference with centralized, even without TXSS
Data CINR:
Without TXSS: Centralized-clustering and Decentralized-clustering are similar
With TXSS:
Decentralized-clustering: average 12 dB CINR is reduced due to TXSS
Centralized-clustering: No impact
Beacon:
Without TXSS
Centralized-clustering: no issue
Decentralized-clustering: 12%~20% STAs have issue to receive Beacon, where CINR less than 7 dB
Beacon CINR in Centralized-clustering is about 10 dB higher than that in Decentralized-clustering
With TXSS
Decentralized clustering: CINR drop 4 dB
Centralized clustering: without impact
Scenario
# S-AP/AP/PCP are impacted by open the door
Decentralized-clustering
8.1
Centralized-clustering 1
Brian Hart, Cisco Systems

18. Simulation Results: ClusterMaxMem=32
Apr 2011
Simulation Results: ClusterMaxMem=32
TXSS impact on decentralized Data
Beacon difference with centralized
Beacon difference with centralized, even without TXSS
Data CINR:
Without TXSS: Centralized-clustering and Decentralized-clustering are similar
With TXSS:
Decentralized-clustering: average 12 dB CINR is reduced due to TXSS
Centralized-clustering: No impact
Beacon:
Without TXSS
Centralized-clustering: no issue
Decentralized-clustering: 15%~20% STAs have issue to receive Beacon, where CINR less than 7 dB
Beacon CINR in Centralized-clustering is about 15 dB higher than that in Decentralized-clustering
With TXSS
Decentralized clustering: CINR drop 4 dB
Centralized clustering: without impact
Scenario
# S-AP/AP/PCP are impacted by open the door
Decentralized-clustering 9
Centralized-clustering 1
Brian Hart, Cisco Systems

19. Conclusions Decentralized-clustering Centralized-clustering Apr 2011
Beacon: Frequency reuse 3+. TXSS of neighbor co-channel clustering makes impact on CINR
Sensitivity to the environment change: multiple s-AP/PCP, member AP/PCP may need to update their cluster role , change cluster offset or change channels
Data:
Frequency reuse is 3+
Big impact from TXSS: CINR 7 dB is reduced due to TXSS
CINR variation is large due to TXSS
Centralized-clustering
Beacon: frequency reuse changes from 3+ to 3xClusterMaxMem+, Beacon can be perfectly received
Sensitivity to the environment change: robust
frequency reuse is still 3+, CINR is similar to that of Decentralized-clustering when the TXSS impact on Decentralized-clustering is not taken into account
Without impact from TXSS
Brian Hart, Cisco Systems

20. Sensitivity Level used in the simulations
Apr 2011
Sensitivity Level used in the simulations
Brian Hart, Cisco Systems

21. Imperfect BF-Antenna Pattern
Apr 2011
Imperfect BF-Antenna Pattern
The impairment antenna pattern is the one used in the simulations
Brian Hart, Cisco Systems

22. Centralized Clustering Formation
Apr 2011
Centralized Clustering Formation
Randomly select the AP on the ceiling to join the Centralized Clustering first
Become an S-AP unless all the channels and Beacon offsets are used up
Failure: if there is no empty Beacon offset detected
Randomly select the PCPs to join the Centralized Clustering
Become a member PCP, if at least one Beacon from S-AP is received with available/empty Beacon offsets.
STAs associate with S-AP, member AP/PCP
90% chance associated with the S-AP, member AP/PCP with the strongest RSSI
10% chance associated with the S-AP, member AP/PCP with the second strongest RSSI
Brian Hart, Cisco Systems

23. Decentralized Clustering Formation
Apr 2011
Decentralized Clustering Formation
Randomly select the AP on the ceiling first
Become an S-AP if there is no Beacon from S-AP received. Randomly select one (of three) channel and set beacon offset 0
Become a member AP if Beacon from an S-AP received with an empty Beacon offset being detected. Set Beacon offset at one of empty Beacon offsets.
Failure: if there is no empty Beacon offset detected
Randomly PCPs to join the Decentralized clustering
Become a S-PCP if there is no Beacon from S-AP/PCP received. Randomly select one (of three) channel and set beacon offset 0
Become a member PCP if a Beacon from a S-AP/PCP received with an empty Beacon offset being detected. Set Beacon offset at one of empty Beacon offsets.
STAs associate with S-AP/PCP, member AP/PCP
90% chance associate with the S-AP/PCP, member AP/PCP with the strongest RSSI
10% chance associate with the S-AP/PCP, member AP/PCP with the second strongest RSSI
Brian Hart, Cisco Systems

24. Apr 2011
CINR Calculation
CINR: STA received signal (from AP/PCP) to interference and noise ratio
Data CINR: (BFed transmitting and BFed receiving)
CINR of STAs in data receiving: the impact of TXSS is not taken into account. Received BF is taken into account
Reason of CINR in Centralized-clustering is a little bit less than that in Decentralized-clustering: more AP/PCPs are assigned in Centralized clustering than that in Decentralized clustering, with more co-channel AP/PCPs
ECPAC-TXSS CBP CINR: (BFed transmitting and BFed receiving)
CINR of STAs in data receiving: when data is transmitted in TXSS CBP
CINR for Beamforming training: similar to CINR of ECPAC-data (due to the beamforing isolation)
Beacon CINR: (BFed transmitting and omni receiving)
Received Beacon CINR at STAs, omni receiving antenna is used
Decentralized Clustering: may face the TXSS of neighbor co-channel clustering. The TXSS impact from neighbor co-channel clustering is not taken into account
Beacon successfully receiving: consider the implementation loss and link margin, it need CINR about 3 dB to successfully the Beacon with control PHY
Brian Hart, Cisco Systems

25. Data/Beacon CINR with TX SS
Apr 2011
Data/Beacon CINR with TX SS
Data CINR with TXSS
Decentralized Clustering: The CINR of STAs in data receiving when facing a TXSS transmission from one neighboring co-channel AP/PCP. We go through all the possible co-channel AP/PCP in the simulation scenario.
Centralized Clustering: will not face such issue when TXSS CBP is required
Beacon CINR with TXSS
Decentralized Clustering: The CINR of STAs in Beacon receiving when facing a TXSS transmission from one neighboring co-channel clustering AP/PCP. We go through all the possible co-channel AP/PCP in the simulation scenario.
Brian Hart, Cisco Systems