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There is no reason that the current spreadsheet can not be used to estimate potential interference
between DECT and PHS, if suitable frequencies can be defined. Reusing the existing channel
bands in the spreadsheet to permit DECT to operate in 1910-1920 MHz and PHS to operate in
1920-1930 MHz using their frequency plans already identified.
1.4.2. AENS View
The spreadsheet is NOT suitable for calculation of the DECT and PHS interference, since the
main feature for this coexistence (the dynamic channel allocation in a shared TDD band) is not
included as input parameter for the used methodology in [1].
In addition, as stated in the last PCC.III meeting, the DECT/PHS interference analysis have been
already “closed”, and it is out of the scope of the current discussions.
Maintain the lockout on the spreadsheet evaluation of interference between PHS and DECT
FWA technologies.
1.5. STEP SIZE DIFFERENTIATION
To differentiate between constant power density steps from linearly falling mask data, the earlier
spreadsheet set the upper bound of a constant step to be 1kHz below the actual value. This
typically causes minimal error for wideband technologies (e.g. DECT, IS-95), but could be
significant for narrowband technologies (e.g. IS-136). Proposed Solution: use 0.1 kHz between
the upper frequency of a constant step from the lower frequency of the next step.
1.5.1. Consensus View
AENS [6] and LMNQ [4, 15] agree that improved step size should be used.
1.6. SPURIOUS INTERFERENCE FROM IS-136
The spreadsheet for [1] used special limits for interference from IS-136 to the 1910-1930 MHz
band.
1.6.1. Consensus View
AENS [6] and LMNQ [4, 15] agree that a minor error (using –48.229 dBm/300Hz instead of –
48.29 dBm/300Hz) should be corrected.
1.6.2. LMNQ View
The Experts agreed [7] to follow official specs. Neither the current mobile spec IS-137A [12]
nor the base spec IS-138A [13] place explicit limits on the 1910-1930 MHz band.
The following extracts from the Mobile station spec IS-137A [12] apply:
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