Project IEEE 802.20 Working Group on Mobile Broadband Wireless Access

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

Title Evaluation Criteria and Traffic Models Status Update

Date Submitted

2004-09-12

Source(s) Farooq Khan 1301 E Lookout Dr. Richardson, TX 75082

Voice: +1 972 761 7929 Fax: +1 972 761 7909 Email: fkhan@sta.samsung.com

Re: 802.20 Call for Contributions: Session # 10 – September 12-17, 2004

Abstract This contribution provides update of 802.20 evaluation criteria group activities.

Purpose Review

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802.20 Evaluation Criteria and Traffic Models Status Update

Farooq Khan

IEEE 802.20 Interim Meeting

Berlin, Germany 

September 12-17, 2004

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Evaluation Criteria Status

• Two AHGs during the May Interim:– Link-system interface– Channel Models

• Five conference calls since May Interim:– 06/06: RF Performance Characteristics– 06/15: Traffic models– 06/29: Link-system interface– 08/24: RF Performance Characteristics– 08/31: Adjacent Channel Interference (ACI) modeling

• Open issues not discussed:– Phased approach, Link budget criteria, application specific

fairness/outage criteria and system simulation calibration etc.

• Updated 802.20 Evaluation Criteria Version 11 document available now:– Evaluation criteria and traffic models documents merged in Version 10– Text proposals on RF performance characteristics and ACI modeling

included in Version 11

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RF Performance Characteristics

• Proposed key RF performance characteristics– Transmitter power, Transmitter Emission Mask, Adjacent

channel (power) Leakage Ratio– Receiver Sensitivity, Receiver Selectivity, Receiver Blocking

• Decided to use normalized Transmitter power– 43dBm/MHz

• Adjacent Channel Interference Modeling– When multiple frequency channels are deployed in an

assigned channel block, the effect of adjacent channel interference modeled and included in the link level simulations.

– A non-linearity model for the power amplifier required (TBD)

• Open issue: 43dBm/MHz power applies to maximum or average PA power?

– FER Link performance curves under the effect of ACI are generated and the result of link performance incorporated into the system level simulation.

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Traffic Models

• Specification of traffic mix– Discussed various possible approaches

– Phase 1 use full buffers model

– A few other traffic scenarios can be defined for the subsequent phase of the simulations, for example:

• Separate simulation with VoIP traffic only

• Separate simulation with web browsing traffic only

• A traffic mix scenario

• FTP traffic model– Decided (06/15/2004) not to modify the “think time” behavior

in the existing FTP traffic model.

• VoIP Traffic Model– Need to finalize on VoIP source traffic model

• Contributions invited on Wireless multi-party Gaming traffic models

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Link-System Interface

• Actual link curves is the default methodology for the link-system interface:

– Can always be used even if an agreement on a common methodology is reached.

• The group is trying to define a common methodology for the link-system interface.

– If a common methodology is used then no justification is required from the proponent

• In the absence of a common methodology, a technology specific methodology can be used if provided with full verification subject to the satisfaction of the group.

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Common LSI Methodology

• A contribution, summarizing different possible methods, was discussed over the 06/29 conference call:– 3GPP2 1xEV-DV/DO Method-1Quasi-Static Method,

– 1xEV-DV/DO Method 2 - Convex Method

– European IST project FITNESS Polynomial based method

– Methods to Predict Performance of Convolutional Codes

– 3GPP Exponential Effective SIR Mapping (EESM) for OFDM

• Need to define the test cases and the accuracy requirements that would be used in the method selection process – The baseline for the accuracy will be actual link curves

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Phased 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.

– Current Recommendation is to use suburban macro, 3 Km/h pedestrian B and 120Km/h Vehicular B channel models.

• The issues that need further consideration:– 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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Link Budget Criteria

• Consensus on most of the link budget parameters

• Open issue: Should maximum range (link budget) or equivalently maximum pathloss be used as a performance

metric for proposal comparison or not?

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Application 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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System 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 simulations need to be calibrated.

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

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Channel Models

• Joint 802.20 Channel Models and Evaluation Criteria AHG (05/13/2004)

• Link-system interface:– Use random phase in the link channel model

– Use actual AoA/AoD in the link/system simulations

• Simplify the SCM in order to make link curves and link-system interface (LSI) approach feasible

• Agree upon the table of model parameters which comply with ITU models

• Other alternative - the procedure to make sure that SCM-MIMO model collapses to ITU SISO model

• Channel mix issue needs to be addressed;

• Investigate the necessity of additional power delay profile randomness across all users

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Conference Calls Schedule

• A total of four conference calls till the November Plenary:

– Tuesday, September 28, 2004, 6-8pmET

– Tuesday, October 12, 2004, 6-8pmET

– Tuesday, October 26, 2004, 6-8pmET

– Tuesday, November 9, 2004, 6-8pmET