August 10, 2005
IEEE P802.20-PD<number>/V<number>
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13 Output Metrics
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In this section, statistics for quantifying the aspects of network-level performance for full buffer user traffic
models are described.
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13.1 User data rate CDF for a fixed specified load and basestation separation
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Figure 1 shows a qualitative example of a cumulative distribution function (CDF) of the distribution of
downlink data rates D( N u , S ) in the interior cells of a network for a specified load/coverage operating
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point
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( N u , S ) where (by definition) the number of full buffer users per cell is ( N u ), and the (nearest
neighbor) basestation separation is ( S ). This distribution of data rates is taken on the ensemble of random
placements of NU full buffer active users in each cell of the network and all other stochastic input
parameters.
Proponents shall provide at least one CDF of user data rates for a fixed load N u and separation S to be
specified by the proponent. CDF plots of user data rates shall be provided for both uplink and downlink
user data rates.
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Figure 1: Service Distribution for a fixed load/coverage operating point
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13.2 Aggregate Throughput vs Basestation Separation at Minimum Service Level
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The downlink minimum service level at each load/coverage operating point, denoted TDL ( N u , S ) , is
defined as the downlink per user data rate which is exceeded at least 90% (TBD) of the time. .For example
in Figure 1, 90% of the full buffer users will be served with a minimum service level of approximately 600
kbits/sec at the load/coverage operating point ( N u , S ) .
August 10, 2005
IEEE P802.20-PD<number>/V<number>
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Proponents shall provide contour plots of constant downlink minimum service levels against full buffer
users per cell versus basestation separation.
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Similarly the uplink minimum service level at each load/coverage operating point is defined as the uplink
per user data rate which is exceeded at least 90% (TBD) of the time.
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Proponents shall provide contour plots of constant uplink minimum service levels against full buffer users
per cell versus basestation separation.
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An example is shown in Figure 2. This example (produced for illustrative purposes), reveals the tradeoff
between the basestation separation ( S ) and the number of full buffer users per cell ( N u ). For example, to
guarantee an expected minimum service rate of, say, 1024 kbits/sec across 90% of the cell area, few full
buffer users (less than 5) can be supported per cell at the inter-base station separation of 6 km. Conversely,
many full buffer users per cell (more than 20) can be supported in the interference-limited case when the
base stations are closely spaced.
Contours of constant T
DL
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128 kbps
Load: Number of users/cell
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256 kbps
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512 kps
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1024 kbps
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1500 kbps
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Coverage: Inter-basestation separation (km)
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Figure 2: Contours of constant minimum service level
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The downlink aggregate throughput per cell ( ADL ) at each load/coverage operating point is the number of
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full buffer users per cell
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D( N u , S ) .
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The proponent shall provide a plot of the downlink aggregate throughput ( ADL ) versus basestation
separation for constant minimum service levels. As an example, the plot resembles Figure 2 with the
vertical axis being aggregate throughput instead of number of users.
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Similarly the proponent shall provide a plot of the uplink aggregate throughput ( AUL ) versus basestation
separation for constant minimum service levels.
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13.3 Computing Spectral Efficiency
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Consistent with the requirements of section 4.1.1 of the adopted 802.20 SRD (v14), the various spectral
efficiency figures shall be computed, separately, for the Downlink (DL) and the Uplink (UL) as follows:
N u multiplied by the mean user data rate of the pdf associated with cdf
August 10, 2005
IEEE P802.20-PD<number>/V<number>
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Use the simulation results to calculate the average throughput per sector, by dividing the aggregate
throughput, across the 19-cell network, by 57.
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2.
Divide the average throughput per sector by the spectrum block assignment size.
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The proponent shall provide plots of the downlink and uplink spectral efficiency versus base-station
separation distance for constant minimum service levels.
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[Prev. Editor’s note: The following 3 options are included corresponding to the options proposed
for section 11: Link Budget, as proposed in ECCG CC contribution: “Eval_LinkBudget1r1.doc”.]
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Option 1:
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13.2
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The maximum data rate that can be supported at the cell boundary at 90% coverage, as indicated
by the appropriate log-normal fade margin, should be provided together with the corresponding
maximum range.
Coverage & Cell boundary data rate
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Option 2:
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[No need for the new section based on the alternative text as proposed by Mike for section 11: link
budget.]
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Option 3:
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13.2
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The maximum range corresponding to a data rate of 128 kbps (TBD) should be computed using
the link budget template for the various cellular test environments: suburban macro, urban macro
and micro, and indoor pico, using channel models as described in the IEEE 802.20 channel
models document.
Maximum range
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Option 4:
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[No need for the new section]