3.2.2 Demodulation of Forward Traffic Channel in Multipath Fading Channel
Last updated: January 15, 2009
This section is only applicable to the lab application.
Definition
Demodulation of Forward Traffic Channel in multipath fading channel is one of the most important receiver tests, for it tests and evaluates how well the AT demodulates the Forward Traffic Channel in the real-world channel conditions (various fading and noise environments.) The figure of merit is Packet Error Rate (PER). The PER is calculated for 38.4 kbps and 76.8 kbps data rates. The following table summarizes the fading tests to be performed
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Channel Simulator Configuration Number
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Description
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1 (8 km/h, 2 paths)
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Case 1 tests the demodulation performance for the 8 km/h, two-path case by checking the PER at the 38.4 kbps and 76.8 kbps data rates.
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|
2 (3 km/h, 1paths)
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Case 2 tests the demodulation performance for the 3 km/h, single-path case by checking the PER at the 38.4 kbps and 76.8 kbps data rates.
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3 (30km/h, 1paths)
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Case 3 tests the demodulation performance for the 30 km/h, single-path case by checking the PER at the 38.4 kbps and 76.8 kbps data rates.
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4 (100 km/h, 3paths)
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Case 4 tests the demodulation performance for the 100 km/h, three-path case by checking the PER at the 38.4 kbps and 76.8 kbps data rates.
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.
Method of Measurement
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Connect the access network emulator, the channel simulator and an AWGN to the AT.
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Set the AN forward packet activity to 100%.
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Set the Control Channel data rate to 38.4 kbps (because the default power level for 38.4 kbps Control Channel is high enough to overcome the interference signals required for these tests).
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Set Pilot Drop to -14 dB (to prevent the access terminal from generating Pilot Strength Measurement Reports due to the low Pilot Channel to AWGN ratio).
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Set Î
or
to -55 dBm/1.23 MHz.
-
Set up a Test Application session and open an FTAP connection (for Subtype 0 or 1 Physical Layer).
-
Perform tests 1 - 24 which evaluate the AT's performance operating at Subtype 0 or 1 Physical Layer for varying E
b
/N
t
. Set I
oc
as specified for each test. The Channel Simulator Configuration number defines the fading profile used for each test case.
-
Set I
oc
as specified for each test (ranges from -63 to -45.9 dBm/1.23 MHz).
-
Set the Forward Traffic Channel data rates (38.4 or 76.8 kbps) as specified for each test.
-
Set the correct Channel Simulator Configuration. Some fading simulator software (for example, Baseband Studio software) has set up all of the parameters for each standard fading profile (such as number of paths, delays, and Doppler shifts), all you need to do is to select the Channel Simulator Configuration number as required for each test.
-
If your AT supports Subtype 2 Physical Layer, set up a Test Application session and open an FETAP connection (for Subtype 2 Physical Layer).
-
Perform tests 25-28 which evaluate the AT's performance operating at Subtype 2 Physical Layer for varying E
b
/N
t
. Set the forward data rate and I
oc
as specified for each test.
-
If your AT supports Subtype 3 Physical Layer and multi-carrier operation, set Pilot Drop to -16 dB. Set up a Test Application session and open an FMCTAP connection (for Subtype 3 Physical Layer).
-
Perform test 29 which evaluate the AT's performance operating at Subtype 3 Physical Layer for varying E
b
/N
t
. Set the forward data rate and I
oc
as specified for each test. Note that the data rate and geometry parameters are on a per carrier basis.
-
Calculate PER for each test.
Minimum Standard
PER shall not exceed 0.3% to 5% with 95% confidence (depending upon data rate and E
b
/N
t
).