Project IEEE 802.20 Working Group on Mobile Broadband Wireless Access

<http://grouper.ieee.org/groups/802/20/>

Title Evaluation Criteria and Traffic Models Update

Date Submitted

2004-03-15

Source(s) Farooq Khan 67 Whippany Road Whippany, NJ 07981

Voice: +1 973 386 5434 Fax: +1 973 386 4555 Email: fkhan1@lucent.com

Re: 802.20 Call for Contributions: Session # 7 – March 15-19, 2004

Abstract This contribution provides update of 802.20 evaluation criteria and Traffic modeling groups activities.

Purpose Review

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802.20 Evaluation Criteria and Traffic Models Update

Farooq Khan

IEEE 802.20 Plenary Meeting

Orlando, FL, USA

March 15-19, 2004

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C802.20-04/038Evaluation Criteria Status

• Four conference calls (1/27, 2/10, 2/24 and 3/9) since Vancouver Interim.

• No activity on Traffic Modeling

• Evaluation criteria discussed the following items:– Simulation of various channel bandwidths, spectral

mask, Phased approach for technology evaluation and Link budget template

• Open issues not discussed:– Interface between link and system simulations,

application specific fairness/outage criteria and system simulation calibration

• Plan for a joint meeting with the channel models group

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C802.20-04/038Various channel bandwidths

• Issues requiring further consideration:

– How the spectral mask requirement would apply to the spectrum allocation used for the evaluation process.

• One possibility is that proposals specify both its channel bandwidth and its "necessary bandwidth” and justify the ability to support their specified number of carriers within the spectrum allocation specified.

• proposals with multiple carriers within the spectrum allocation used for the evaluation process may have to simulate the inter-carrier leakage in order to justify the number of carriers used within the allocation.

– A value for the spectrum allocation used for the evaluation process.

Specify a small number (preferably one) of spectrum allocations[1] (over which the results are quoted). The individual technology proposals may then split the total spectrum into a given number of carriers and specify their reuse factor and channel bandwidth[2]. For example, if XMHz (TBD) is specified as the spectrum allocation to be used for the evaluation process, then individual technology proposals can perform simulations and then scale the simulation output data to that spectrum allocation (XMHz). For proposals with channel bandwidths that are smaller than that spectrum allocation, it would also be possible to simulate multiple carriers per sector and to collect data from all the carriers that can be supported within that spectrum allocation. [1] See definition of spectrum allocation from the Terminology Annex of Requirements Document.[2] See definition of channel bandwidths from the Terminology Annex of Requirements Document.

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C802.20-04/038Phased Approach

• The details of phase 1 are currently being discussed in the evaluation criteria:– Agreed to use 19-cells 3-sector wrap-around configuration, Full

buffers (hungry) traffic, simulation calibration, link-system interface etc.

• The issues that need further consideration:– Channel model(s) used, Full-duplex simulation, and handoff modeling

etc.

The 802.20 evaluation will be structured with multiple phases with each phase progressively adding more complexity. The evaluation work for each proposal may then be compared at each phase to ensure a progressive "apples to apples" comparison of proposals. This structured approach will also provide performance metrics for the physical and link layer performance early rather than later in the evaluation process. Phase 1 of the evaluation will consist of: - Items/issues/criteria that are required for the calibration of simulations - Items/issues/criteria that will draw out the important differences between the various proposals that cannot be otherwise inferred. The goals at the end of phase 1 are, first, to achieve confidence that different simulation models are calibrated and, two, to present fundamental performance metrics for the physical and link layer of various proposals.

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C802.20-04/038Link Budget

• Discussion on Link budget over the last 2 conference calls (2/24 and 3/9):

• Multiple proposals for the link budget parameters (need convergence on a single set of parameter values):– Antenna gain for BS and MS

– Cable, connector, and combiner losses

– Body Losses

– Building/vehicle penetration Loss

– Receiver noise figure at BS and MS

– Max Transmitter power at the base station (BS) and mobile station (MS) – How to account for power amplifier back-off?

• Plan to meet in an Ad Hoc group for further discussion on link budget parameters.

• Open issue: Should maximum range (link budget) be used as a performance metric for proposal comparison or not?

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C802.20-04/038Link-system Interface (LSI)

• The evaluation criteria agreed to specify an acceptable interface between link and system simulations. – This is needed because the link and system simulations

are performed separately (the simulation complexity would be very high if joint link and system simulations are required).

• Two potential solutions to the link-system interface:– Use actual link curves

– Specify an LSI methodology

• Contributions are invited on this topic

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C802.20-04/038Application specific criteria

• A fairness criteria is defined for the best effort data traffic:

– application specific outage and QoS (FER, delay etc.) criteria need to be defined for other applications!

• Contributions are also invited on additional fairness metrics

In the evaluation of spectral efficiency and in order to make a fair comparison of different proposals, it is important that all mobile users be provided with a minimal level of throughput. The fairness for best effort traffic (HTTP, FTP and full buffers) is evaluated by determining the normalized cumulative distribution function (CDF) of the user throughput, which meets a predetermined function. For applications other than best effort, application specific outage criteria are defined. The proposals will also provide additional fairness metrics. The details of the additional fairness metrics are TBD (see for example IEEE C802.20-04/05).

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C802.20-04/038System simulation calibration

• The evaluation criteria would specify a system simulation calibration process.– Calibration would be done as part of phase 1 of

simulations

• However, it is not clear, at this stage, to what level of detail different simulations need to be calibrated.

• The group is open to proposals to nail down the calibration specifications.

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C802.20-04/038Traffic Models

• Items requiring further consideration:– Specification of traffic mix

• Currently only a list of traffic types is provided, Issue of percentage of various traffic types in a mixed scenario is still open.

• Contributions invited on possible traffic mix scenarios.

– FTP traffic model• Contributions invited on whether we need to modify the

“think time” behavior in the existing FTP traffic model.

– VoIP Traffic and Wireless multi-party Gaming traffic models

• Overview of possible VoIP traffic models during the Vancouver Interim

• Contributions invited on possible VoIP and gaming traffic models to be used in system simulations.