Some propositions to progress towards the PAR definition June 2013 doc.: IEEE 802.11-12/xxxxr0 November 2013 Some propositions to progress towards the PAR definition Authors: Date: 2013-xx-11 Laurent Cariou (Orange)
June 2013
Content This document mentions different topics that need to be discussed for the definition of the PAR « scope » and « explanatory notes » sections to identify what elements to include in each sections and how to describe them For each topic, this document presents some propositions we would like to sense the group feeling on these propositions Based on some propositions for these different topics, this document also presents a PAR proposal Laurent Cariou (Orange)
Some propositions on PAR content The objectives of HEW need to be explained using simple words in the scope section. Explanatory notes are used to provide further details to better understand the directions for the group. First part: Scope Laurent Cariou (Orange)
What are the Salient PAR Topics? Scenarios PHY/MAC and bands of operation (3) General objectives (4) Detailing the objectives in the explanatory notes (5) Backward compatibility In the following slides we discuss the above topics and arrive to a proposed PAR: This amendment defines standardized modifications to both the 802.11 physical layers (PHY) and the 802.11 Medium Access Control Layers (MAC) in the 2.4 and 5GHz unlicensed bands that enable a significant user experience and throughput enhancement, as measured at the MAC data service access point (SAP), for all HEW stations in high density, indoor and outdoor, real-world environments. Such improvements shall also lead to significant area throughput increase. Slide 5 Laurent Cariou (Orange)
Some propositions on PAR scope content (1) Scenarios Scenarios are key in the definition of HEW objectives and should therefore be described in the scope section. However, they can’t be described in details proposition to describe it only by the a sentence similar to the following text in the scope section: high density, indoor and outdoor, real-world environments proposition to provide further details in the explanatory notes and to reference the simulation scenario working document made during the SG phase, “5 real-world scenarios representing high density, indoor and outdoor usages defined in the working document XXXXr0x developed by HEW SG” mentioning of course that the simulation scenario official document will be made during WG (alternatively, we could just mention that SG initiated the creation of simulation scenarios…) Laurent Cariou (Orange)
Some propositions on PAR scope content (2) PHY/MAC and bands of operation The scope should mention the modifications of PHY and MAC layers. The scope should mention the bands of operations targetted by HEW: 2.4 and 5GHz unlicensed bands. Laurent Cariou (Orange)
Some propositions on PAR scope content (3) General objectives Proposed text for the objectives definition in the scope section proposition to define the objectives without entering the debate on metrics (part of the evaluation methodology, work belonging to WG) proposition not to quantify the gains in the PAR (mention to significant improvement only) proposition to define the objective as the improvement of user experience and of throughput (MAC SAP) for all HEW stations user experience is vague (achieved by minimum throughput and potentially other metrics) benefits for all stations: to ensure that the aggregated throughput gains are not obtained by only a very limited proportion of the stations proposition to define a mention to area throughput, as a consequence of the described objective proposition to further detail the metrics in the explanatory notes Laurent Cariou (Orange)
Some propositions on PAR content (4) Detailing the objectives in the explanatory notes Since gains would not be quantified in the PAR, we propose to provide further details on the objectives, in the explanatory notes, and to define the different ways that have already been identified to enable the improvements for instance: Objective related to high density of STAs per BSS: manage interference between STAs, increase airtime usage efficiency, improve I throughput distribution on the whole BSS coverage Objective related to scenarios with high density of STAs and BSSs: increase reuse between neighboring OBSSs, improve interference control between overlapping networks not sharing the same management entity, increase airtime usage ratio between data and management frames Objective related to outdoor deployments: increase robustness to outdoor propagation characteristics (delay spread, Doppler), increase uplink transmission reliability Laurent Cariou (Orange)
Some propositions on PAR content (5) Backward compatibility It is important to mention backward compatibility and coexistence in the PAR. proposition to mention it in the scope section or in the explanatory notes proposition to reuse similar words as for 11n/11ac: This new amendment shall include modes of operation that ensures backward compatibility and coexistence with legacy IEEE802.11 devices in the 2.4 and 5 GHz unlicensed band Laurent Cariou (Orange)
Proposal for 802.11 HEW PAR Scope This amendment defines standardized modifications to both the 802.11 physical layers (PHY) and the 802.11 Medium Access Control Layers (MAC) in the 2.4 and 5GHz unlicensed bands that enable a significant user experience and throughput enhancement, as measured at the MAC data service access point (SAP), for all HEW stations in high density, indoor and outdoor, real-world environments. Such improvements shall also lead to significant area throughput increase. Slide 11 Laurent Cariou (Orange)
Some propositions on PAR content The objectives of HEW need to be explained using simple words in the scope section. Explanatory notes are used to provide further details to better understand the directions for the group. Second part: Explanatory notes Laurent Cariou (Orange)
Proposal for 802.11 HEW PAR Explanatory Notes Text for Metrics (1) Existing 802.11 standards are typically designated by their peak throughput in optimal theoretical conditions. This amendment has chosen to use performance metrics representative of the throughput obtained by stations in real-world conditions. The value of these metrics are strongly dependent on the scenarios used for the evaluation. These metrics will therefore be used to measure the relative improvements with regards to previous 802.11 amendments (802.11n in 2.4GHz and 802.11ac in 5GHz) rather than to measure absolute values. One of the key objective of HEW is to improve throughputs for all stations in environments with high density of APs and STAs. For that reason, the distribution of throughput between stations is captured in the chosen metrics. Average per user throughput and 5 percentile of users throughput CDF are therefore two important complementary metrics. Slide 13 Laurent Cariou (Orange)
Proposal for 802.11 HEW PAR Explanatory Notes Text for Scenarios/Objectives (2) The evaluation of solutions will be based on a set of real-world scenarios representative of the main expected usage models that are mainstream and expected to suffer bottleneck in the incoming years. These real world scenarios capture all the problems that currently strongly limit (or will strongly limit in the incoming years) throughput and quality of experience. HEW SG initiated the creation of usage models, simulation scenarios and evaluation methodology documents for this purpose (reference TBD) Solving these identified problems is key to fulfil HEW general goal, and represent multiple objectives. Three categories have already been identified. Objective related to high density of STAs per BSS: manage interference between STAs, increase airtime usage efficiency, increase throughput distribution on the whole BSS coverage Objective related to scenarios with high density of STAs and BSSs: increase reuse between neighboring OBSSs, improve interference control between overlapping networks not sharing the same management entity, increase airtime usage ratio between data and management frames Objective related to outdoor deployments: increase robustness to outdoor propagation characteristics (delay spread, Doppler), increase uplink transmission reliability Slide 14 Laurent Cariou (Orange)
Proposal for 802.11 HEW PAR Explanatory Notes Text for additional requirements (3) This new amendment shall include modes of operation that ensures backward compatibility and coexistence with legacy IEEE802.11 devices in the 2.4 and 5 GHz unlicensed band Though the primary objective used in the scope of the project deals with increased per-user throughput by improving efficiency in the resources utilization, the intent is also to provide enhancements on: energy efficiency, range of operation, … Slide 15 Laurent Cariou (Orange)
June 2013 Strawpolls Do you approve to progress on the PAR definition by using the PAR scope proposal in slide 11 as the HEW PAR scope baseline (Y/N/A) Laurent Cariou (Orange)
Annexes Slide 17 Laurent Cariou (Orange)
11n PAR Slide 18 Laurent Cariou (Orange) The scope of this project is to define an amendment that shall define standardized modifications to both the 802.11 physical layers (PHY) and the 802.11 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). The scope of the MAC and PHY enhancements assume a baseline specification defined by 802.11 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 802.11a and/or 802.11g. Existing 802.11 standards are typically designated by their peak physical data rates. For example, 802.11a 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 802.11 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. 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. Slide 18 Laurent Cariou (Orange)
11ac PAR This amendment defines standardized modifications to both the 802.11 physical layers (PHY) and the 802.11 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 IEEE802.11 devices in the 5 GHz unlicensed band. Additional Explanatory Notes: (Item Number and Explanation) 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) Slide 19 Laurent Cariou (Orange)