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1xEV-DO Signaling
R&S
®
CMW-KM8xx/-KS8xx
38
User Manual 1173.9511.02 ─ 12
Termination Target PER > Confidence Level
The statistical probability that the Termination Target PER is below the configured
reverse link PER limit (see
chapter 2.2.14.4, "Statistical PER Tests (Confidence Test-
Termination Target PER > PER
The rate of MAC packets the R&S
CMW failed to receive successfully within the appli-
cable Termination Target
For the test procedure refer to
2.2.14.4
Statistical PER Tests (Confidence Testing)
In a normal packet error rate test, a fixed number of packets is transmitted, leading to a
fixed test time for each PER result. The idea behind statistical testing is to apply proba-
bility theory and predict a range for the PER at an early stage of the measurement. The
prediction can be used to stop the measurement if the probability of the AT to pass or
fail the receiver quality test is large enough (early pass or early fail decision). Statistical
testing can reduce test times considerably, especially if the exact PER of a receiver is
very low or very high.
Probability distribution
Confidence PER tests are based on the statistical independence of the packet error
events: The probability of a packet error is equal for each received packet. The exact
packet error rate is given by the limit of the ratio n
e
/n
s
, where n
e
denotes the number of
packet errors and n
s
the number of received packets, and where the number of
received packets tends to infinity. Any real packet error rate test necessarily provides
an approximation to the exact packet error rate.
Given the statistical independence of the packet error events, the probability p for any
number of packet errors n
e
at a given exact PER and a given number of received pack-
ets n
s
can be described by a Poisson distribution or an appropriate approximation such
as the chi-squared distribution. The distribution is centered on the exact PER and
becomes narrower as n
s
increases.
Estimates of the exact PER are based on such a distribution. The distribution also pro-
vides the probability for the estimated PER to be below any specified Maximum PER.
Min. confidence level
A statistical PER test is configured by means of the "Max PER" and the "Min Confi-
dence Level". The test is stopped as soon as the probability for the estimated PER to
be below the "Max PER" exceeds the "Min Confidence Level".
To activate a statistical PER test, a "Min Confidence Level" must be defined and an
appropriate "Stop Condition" must be set.
General Description
深圳德标仪器
135-1095-0799