1. How to Describe 802.11ax Functional Requirements
May 2013
doc.: IEEE /xxxxr0
May 2014
How to Describe ax Functional Requirements
Date:
Authors:
Name
Affiliations
Address
Phone
Minho Cheong
NEWRACOM
193 Moonjiro, Yuseong-Gu, Daejeon, Korea
Minho Cheong, NEWRACOM
Osama Aboul-Magd (Huawei Technologies)

2. May 2014
Abstract
This presentation gives set of issues on how to describe ax functional requirements based on the PAR document we agreed
Minho Cheong, NEWRACOM

3. PAR What it is When to do What it has Characteristics May 2014
Specify the scope & purpose of the task group activity
When to do
As an outcome of the study group to prepare the task group activity itself
What it has
Scope of proposed project
Purpose of proposed project
Additional explanatory notes
Characteristics
Sometimes, it admits relative numbers or qualitative description
It can have some more contents in its explanatory notes if they are helpful for guidance
Minho Cheong, NEWRACOM

4. Functional Requirements
May 2014
Functional Requirements
What it is
Specify the basic core of mandatory features (derived from PAR)
When to do
As an outcome of the earlier stage of the task group to prepare draft description (or spec. framework document)
What it has
Requirements for system performance
Requirements for user experience
Requirements for backward compatibility & coexistence
Compliance to PAR
Characteristics
Should be quantitative with absolute numbers
Having more detail compared to the PAR
Minho Cheong, NEWRACOM

5. Relation between PAR & FR (802.11n)
May 2014
Relation between PAR & FR (802.11n)
Requirements
PAR
(gray: explanatory notes) FR
Note
Max. per-user throughput
> 100Mbps at MAC SAP
> 4 times compared to before
Max. per-user throughput using 20MHz channel
More strict requirement than the above
Band
5GHz (as well as 2.4GHz)
Backward compatibility
11g/11a
Interoperability
11g/11a (11n AP can control)
QoS
11e support
Peak spectral efficiency
> 3bps/Hz
PHY rate
Single SS mode
(peak rate)
> 50Mbps at MAC SAP
To allow SISO mode
(interoperability)
support
Compliance to PAR
Needless to say
YES
Minho Cheong, NEWRACOM

6. Relation between PAR & FR (802.11ah)
May 2014
Relation between PAR & FR (802.11ah)
Requirements
PAR
(gray: explanatory notes) FR
Note
Band
Below 1GHz excluding TVWS
(enumerating some countries)
Coexistence
& g
Data rate
> 100kbps
>100kbps (PHY rate)
To differentiate from g
Coverage
Up to 1km
Up to 1km (under regulations)
Btw. rate & coverage
Shall optimize
Shall support the above two requirements at the same time
Maximum throughput
of high data rate mode
> 20Mbps (aggregated on multi-STAs at PHY SAP)
To allow high data rate offloading mode
Modulation
OFDM
Number of associations
> 2007 (for outdoor)
To cover sensors
User experience
Maintain user experience
Power saving
Shall support enhanced one
Compliance to PAR
Needless to say
YES
Minho Cheong, NEWRACOM

7. Relation between PAR & FR (802.11ac)
May 2014
Relation between PAR & FR (802.11ac)
Requirements
PAR
(gray: explanatory notes) FR
Note
Maximum multi-STA throughput
> 1Gbps at MAC SAP
(utilizing no more than 80MHz)
Set minimum BW
Maximum single-link throughput
> 500Mbps at MAC SAP
Throughput (general)
Enhancement over n
Needless to say
Band
< 6GHz excluding 2.4GHz
5GHz band
Backward compatibility
Legacy in 5GHz band
802.11a/11n in 5GHz band
Coexistence
Example of technology
Multiple simultaneous comm.
Hint on MU-MIMO
Example of scenario
BSS (1 AP & 3 or more STAs)
At least 3 STA’s
Range of operation
Difficult to achieve
Aggregate network capacity (spectrum efficiency)
Difficult to quantify
Power consumption (peak & average)
Compliance to PAR
YES
Minho Cheong, NEWRACOM

8. Observations from History
May 2014
Observations from History
PAR
Try to give a number on the most important metric (if possible)
Admit relative numbers or qualitative description (if inevitable)
Try some technical examples with very comprehensive expressions (if needed in the explanatory notes)
Functional Requirements
Strongly prefer numbers (especially, absolute numbers)
Numbers shall be easily measurable in reality
Shall not give any ambiguity when being read
Try to specify the coupled relation (if exists between key metrics)
Minho Cheong, NEWRACOM

9. 802.11ax (HEW) PAR May 2014 5.2.b. Scope of the project:
This amendment defines standardized modifications to both the IEEE physical layers (PHY) and the IEEE Medium Access Control layer (MAC) that enable at least one mode of operation capable of supporting at least four times improvement in the average throughput per station (measured at the MAC data service access point) in a dense deployment scenario, while maintaining or improving the power efficiency per station.
This amendment defines operations in frequency bands between 1 GHz and 6 GHz. The new amendment shall enable backward compatibility and coexistence with legacy IEEE devices operating in the same band.
Minho Cheong, NEWRACOM

10. 802.11ax (HEW) PAR 5.5 Need for the Project: ~ellipsis~
May 2014
802.11ax (HEW) PAR
5.5 Need for the Project:
~ellipsis~
Unlike previous amendments where the focus was on improving aggregate throughput, this amendment focuses on improving metrics that reflect user experience, such as average per station throughput, the 5th percentile of per station throughput of a group of stations, and area throughput. Improvements will be made to support environments such as wireless corporate office, outdoor hotspot, dense residential apartments, and stadiums.
Minho Cheong, NEWRACOM

11. May 2014
802.11ax (HEW) PAR
8.1 Additional Explanatory Notes (Item Number and Explanation):
The focus of this amendment is on WLAN indoor and outdoor operation in the 2.4 GHz and the 5 GHz frequency bands. Additional bands between 1 GHz and 6 GHz may be added as they become available.
The increase in average throughput per station is not limited to four times improvement. Improvement values in the range of 5-10 times are targeted, depending on technology and scenario.
Outdoor operation is limited to stationary and pedestrian speeds.
Average throughput per station is directly proportional to both aggregate basic service set (BSS) throughput and area throughput. The 5th percentile measure of the per station throughput may be used to determine that the desired distribution of throughput among a number of stations in an area is satisfied. These metrics, along with the satisfaction of the packet delay and the packet error ratio (PER) requirements of applications, will directly correspond to user experience in identified scenarios.
Minho Cheong, NEWRACOM

12. May 2014
802.11ax (HEW) PAR
Since the values of the metrics of interest will depend on the scenario, the focus will be on the relative improvement of these metrics compared to previous IEEE amendments (IEEE n in 2.4 GHz and IEEE ac in 5 GHz).
The amendment will be evaluated with a set of typical deployment scenarios representative of the main expected usage models that are likely to suffer bottlenecks in the coming years: residential, enterprise, indoor and outdoor hotspots. HEW SG has initiated the creation of a high-level simulation scenario working document (ref: 11-13/1001r5) to model these scenarios. The simulation scenarios may include system characteristics extracted from measured IEEE operations in the field.
Minho Cheong, NEWRACOM

13. May 2014
802.11ax (HEW) PAR
These scenarios highlight three categories of objectives to improve WLAN efficiency:
Make more efficient use of spectrum resources in scenarios with a high density of STAs per BSS.
Significantly increase spectral frequency reuse and manage interference between neighboring overlapping BSS (OBSS) in scenarios with a high density of both STAs and BSSs.
Increase robustness in outdoor propagation environments and uplink transmissions.
This project may include the capability to handle multiple simultaneous communications in both the spatial and frequency domains, in both the uplink (UL) and downlink (DL) direction.
Power efficiency is intended to measure consumption of devices which can reasonably be assumed to be powered by batteries and will take into account average power consumption for a given scenario
Minho Cheong, NEWRACOM

14. Relation between PAR & FR (802.11ax)
May 2014
Requirements
PAR (gray: explanatory notes)
FR issues now
Note
Per-STA throughput
More than 4 times (Average per-STA throughput)
(Up to 10 times to be tried)
Qualitative or Quantitative?
(just keeping X times?)
FR may need a detailed representative scenarios
Area throughput
Not defined. Just mentioned as one of metrics which impact on user experience
(Can be derived from 5th % per-STA throughput)
Seems duplicative to define in detail
User experience
Just lists up several metrics which impact on user experience
Average per-STA throughput, 5th % per-STA throughput, area throughput,
Packet delay, PER
(just keeping listing of related metrics?)
Band
1~6GHz (specially 2.4GHz and 5GHz)
Backward compatibility
Legacy devices in 2.4 & 5GHz
(allows no exceptions)
Coexistence
Example of problems
3 main problems re-mentioned here
NONE
Example of technology
Multiple simultaneous comm. in several dimensions
Example of scenario
802.11ax sim. Scenario doc. introduced
802.11ax sim. Scenario doc. Introduced
(picking representative scenarios?)
Range of operation
Outdoor hotspot included
(outdoor limited to pedestrian or stationary)
(range up to X meters?)
Power efficiency
Maintaining or preserving (more than 100 %)
(Average power consumption to be considered)
Compliance to PAR
Needless to say
YES
Minho Cheong, NEWRACOM

15. Stages to Go from PAR to FR
May 2014
Stages to Go from PAR to FR
Until now
Stage 0: We have the (qualitative) PAR just based on our intuition
Because we didn’t want any delay due to hard work in the SG phase
Current issue
Do we still allow simple qualitative FR (just copy of PAR) to prevent hard work for check in the earlier stage of TG?
Or Does FR need to be more quantitative with absolute numbers (e.g., minimum or maximum limitation)
Stage 1: Less simplified simulation check to get absolute numbers
Use a set of simulation scenarios defined in the official doc.
(Try to get consensus on just initial set of HEW technology for trial)
Check simulation results with that technology & get absolute numbers
Stage 2: Functional Requirements doc. with absolute numbers
Minho Cheong, NEWRACOM

16. May 2014
References
hew-from-PAR-to-functional-requirements-of-HEW
hew hew-sg-proposed-par
hew-ieee hew-sg-proposed-csd
Minho Cheong, NEWRACOM

17. May 2014
Appendix
Minho Cheong, NEWRACOM

18. e.g., 802.11n (PAR) May 2014 12. Scope of Proposed Project:
The scope of this project is to define an amendment that shall define standardized modifications to both the physical layers (PHY) and the Medium Access Control Layer (MAC) so that modes of operation can be enabled that are capable of much higher throughputs, with a maximum throughput of at least 100Mbps, as measured at the MAC data service access point (SAP).
 13. Purpose of Proposed Project: 
The purpose of the project is to improve the wireless local area network (LAN) user experience by providing significantly higher throughput for current applications and to enable new applications and market segments. 
Minho Cheong, NEWRACOM

19. e.g., 802.11n (PAR) May 2014 Additional Explanatory Notes:
The scope of the MAC and PHY enhancements assume a baseline specification defined by and its amendments and anticipated amendments a, b, d, e, g, h, i and j. The enhancements shall be to support higher throughput. The amendment shall not redefine mechanisms in the baseline that do not pertain to higher throughput.
Some of the modes of operation defined in the HT amendment shall be backwards compatible and interoperable with a and/or g.
Existing standards are typically designated by their peak physical data rates. For example, a has a peak data rate of 54Mbps. This amendment has chosen to use a performance metric of throughput measured at the MAC data SAP. This amendment seeks to improve the peak throughput to at least 100Mbps, measured at the MAC data SAP. Depending on the scenario, this represents an improvement of at least 4 times the throughput obtainable using existing systems.
In order to make efficient use of scarce spectral resources in unlicensed bands, the highest throughput mode defined by the HT amendment shall achieve a spectral efficiency of at least 3 bits per second per Hertz for the PSDU.
Minho Cheong, NEWRACOM

20. e.g., 802.11n (PAR) May 2014 Additional Explanatory Notes:
In the process of formulating this PAR, it was found that there are multiple user scenarios. Accordingly, the task group will undertake the following steps:
1. Identify and define usage models, channel models and related MAC and application assumptions. Initial usage models envisioned include hot-spot, enterprise and residential; others may be included.
2. Identify and define evaluation metrics that characterize the important aspects of a particular usage model. The evaluation metrics may include but are not limited to the items listed in Table 1, provided as an illustration of the format.
3. Develop a technical requirement specification.
4. Define a process for evaluations.
The impact of an HT device on the operation of a legacy network shall be comparable to that of any other legacy device identified in the baseline defined above.
Minho Cheong, NEWRACOM

21. e.g., 802.11n (Functional Requirements)
May 2014
e.g., n (Functional Requirements)
Number
Name
Requirement 1
Single Link HT rate supported
Demonstrate at least one set of conditions under which 100 Mbps at the top of the MAC SAP can be achieved. Provide all relevant information to document this. 2
HT rate supported in 20MHz channel
Proposal supports at least one mode of operation that supports 100Mbps throughput at the top of the MAC SAP in a 20MHz channel.
Provide all relevant information to document this. 3
Supports 5GHz bands
Protocol supports 5GHz bands (including those supported by .11a) 4
.11a backwards compatibility
Some of the modes of operation defined in the proposal shall be backwards compatible with a. 5
.11g backwards compatibility
If it supports 2.4 GHz operation, some of the modes of operation defined in the proposal shall be backwards compatible with g.
Minho Cheong, NEWRACOM

22. e.g., 802.11n (Functional Requirements)
May 2014
e.g., n (Functional Requirements)
Number
Name
Requirement 6
Control of support for legacy STA from .11n AP
A .11n AP can be configured to reject or accept associations from legacy STA because they are legacy STA. 7
.11e QoS support
The proposal shall permit implementation of the e amendment within a .11n STA 8
Spectral Efficiency
The highest throughput mode of the proposal shall achieve a spectral efficiency of at least 3 bps/Hz for the PSDU 9
Compliance to PAR
The proposal complies with all the mandatory requirements of the PAR [5] and 5 Criteria [6] 10
Existence of single spatial stream transmission modes
Proposal shall define single spatial stream transmission modes that provide at least one mode of operation that supports a maximum throughput of at least 50 Mbps in a 20MHz channel as measured at the MAC data SAP. 11
Interoperability with single spatial stream non AP stations
A .11n AP or STA shall interoperate with a single spatial stream entity defined as a non-AP STA that complies with the .11n proposal with the exception of only supporting single spatial stream transmission modes as required by FR10.
Minho Cheong, NEWRACOM

23. e.g., 802.11ah (PAR) May 2014 5.2 Scope of Proposed Standard:
This amendment defines an Orthogonal Frequency Division Multiplexing (OFDM) Physical layer (PHY) operating in the license-exempt bands below 1 GHz, e.g., MHz (Europe), 950 MHz -958 MHz (Japan), MHz, MHz, MHz, and MHz (China), 917 – MHz (Korea) and MHz (USA), and enhancements to the IEEE Medium Access Control (MAC) to support this PHY, and provides mechanisms that enable coexistence with other systems in the bands including IEEE and IEEE P g. The data rates defined in this amendment optimize the rate vs. range performance of the specific channelization in a given band.
This amendment also adds support for:
transmission range up to 1 km
data rates > 100 kbit/s
while maintaining the WLAN user experience for fixed, outdoor, point to multi point applications.
Minho Cheong, NEWRACOM

24. e.g., 802.11ah (PAR) 5.4 Purpose of Proposed Standard: May 2014
The purpose of this amendment defines operation of license-exempt wireless networks in frequency bands below 1 GHz excluding the TV White Space bands.
Minho Cheong, NEWRACOM

25. May 2014
e.g., ah (PAR)
8.1 Additional Explanatory Notes: (Item Number and Explanation)
None
Minho Cheong, NEWRACOM

26. e.g., 802.11ah (Functional Requirements)
May 2014
e.g., ah (Functional Requirements)
2.1 System Performance Supporting band TGah R1 – The TGah amendment shall describe operation in the license-exempt band below 1 GHz excluding the TV White Space bands. Example operating bands could include one or more of the following: MHz (Europe), MHz (Japan), MHz (China), MHz (Korea), MHz, MHz (Singapore) and MHz (U.S.) Coverage and data rate TGah R2 – The TGah amendment shall support mode of operation in which PHY data rate at least 100 Kbps is provided with coverage of 1km under regulatory constraints. TGah R3 – The TGah amendment shall provide at least a mode of operation capable of achieving a maximum aggregate Multi-Station data rate of 20Mbps as measured at the PHY data service access point (SAP) in S1G band.
Minho Cheong, NEWRACOM

27. e.g., 802.11ah (Functional Requirements)
May 2014
e.g., ah (Functional Requirements)
2.1.3 OFDM PHY modulation TGah R4 – The TGah amendment shall use an Orthogonal Frequency Division Multiplexing (OFDM) PHY modulation Number of associations TGah R5 – The TGah amendment shall support a mode of operation that supports the number of associations beyond 2007 for outdoor applications. 2.2 Mainintaining the User Experience TGah R6 – The TGah amendment shall maintain the network architecture of the system for fixed, outdoor, point-to-multi-point applications and support compability to management plane defined in the existing standard and its amendments.
Minho Cheong, NEWRACOM

28. e.g., 802.11ah (Functional Requirements)
May 2014
e.g., ah (Functional Requirements)
2.3 Coexistence with and g devices TGah R7 – The TGah amendment shall provide a mechanism to enable coexistence with other systems in the bands including and g. 2.4 Enhanced Power Saving TGah R8 – The TGah amendment shall provide an enhanced power saving mechanism to support battery-powered operation with long replacement cycle. 2.5 Compliance to PAR TGah R9 - The proposal complies with the PAR and 5 Criteria.
Minho Cheong, NEWRACOM

29. e.g., 802.11ac (PAR) 5.2 Scope of Proposed Standard: May 2014
This amendment defines standardized modifications to both the physical layers (PHY) and the Medium Access Control Layer (MAC) that enable modes of operation capable of supporting: A maximum multi-station (STA) throughput (measured at the MAC data service access point), of at least 1 Gbps and a maximum single link throughput (measured at the MAC data service access point), of at least 500 Mbps.
Below 6 GHz carrier frequency operation excluding 2.4 GHz operation while ensuring backward compatibility and coexistence with legacy IEEE devices in the 5 GHz unlicensed band.
Minho Cheong, NEWRACOM

30. e.g., 802.11ac (PAR) 5.4 Purpose of Proposed Standard: May 2014
The purpose of the amendment is to improve the wireless local area network (LAN) user experience by providing significantly higher basic service set (BSS) throughput for existing WLAN application areas and to enable new market segments for operation below 6 GHz including distribution of multiple multimedia/data streams.
Minho Cheong, NEWRACOM

31. May 2014
e.g., ac (PAR)
8.1 Additional Explanatory Notes: (Item Number and Explanation)
5.2) The project may include the capability to handle multiple simultaneous communications. • The multi-STA throughput is defined as the sum of the MAC SAP throughputs across all active transmissions within a set of STAs. • The 1 Gbps maximum multi-STA throughput may be achieved when considering multiple simultaneously actively-communicating STAs, e.g., a BSS with 1 access point (AP) and 3 or more STAs. • Though the primary metric used in the scope of the project deals with MAC SAP throughput, the intent is to provide enhancements over IEEE802.11n on the following inter-dependent performance indicators: throughput at the MAC data SAP, range of operation, aggregate network capacity (spectrum efficiency), power consumption (peak and average).
1.1) This is an amendment to the then current revision of the IEEE standard
Minho Cheong, NEWRACOM

32. e.g., 802.11ac (Functional Requirements)
May 2014
e.g., ac (Functional Requirements)
2.1 System Performance Multi-STA throughput measured at the MAC SAP to be at least 1 Gbps. TGac R1 – The TGac amendment shall provide at least a mode of operation capable of achieving a maximum Multi-Station aggregate throughput of more than 1 Gbps as measured at the MAC data service access point (SAP), utilizing no more than 80 MHz of channel bandwidth in 5 GHz band Single-STA throughput measured at the MAC SAP to be at least 500 Mbps. TGac R2 – The TGac amendment shall provide at least a mode of operation capable of achieving a maximum Single-Station throughput of more than 500 Mbps as measured at the MAC data service access point (SAP), utilizing no more than 80 MHz of channel bandwidth in 5GHz band.
Minho Cheong, NEWRACOM

33. e.g., 802.11ac (Functional Requirements)
May 2014
e.g., ac (Functional Requirements)
2.2 Backward Compatibility with a/n devices operating in 5 GHz Refer to the IEEE Std , section 3.1 for the definitions of backward compatible. TGac R3- The TGac admendment shall provide backward compatibility with IEEE802.11a devices operating in the 5 GHz frequency band. TGac R4- The TGac admendment shall provide backward compatibility with IEEE802.11n devices operating in the 5 GHz frequency band.
Minho Cheong, NEWRACOM

34. e.g., 802.11ac (Functional Requirements)
May 2014
e.g., ac (Functional Requirements)
2.3 Coexistence with a/n devices operating in 5 GHz Refer to the IEEE Std , section 3.1 for the definitions of coexistence. TGac R5 – The TGac amendment shall provide mechanisms that ensure coexistence between TGac and legacy IEEE802.11a/n devices. 2.4 Compliance to PAR TGac R6 - The proposal complies with the PAR and 5 Criteria.
Minho Cheong, NEWRACOM