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LTE RS Power Calculation-04052016
HUAWEI TECHNOLOGIES CO., LTD.
RS Power Calculation
Type A symbols are those that appear during a symbol period when there is no
reference signal.
Type B symbols are those that appear during a symbol period when there are
reference signals.
The ratio of PDSCH EPRE to cell-specific RS EPRE among PDSCH
REs (not applicable to PDSCH REs with zero EPRE) for each OFDM
symbol is denoted by either A or B
A =P(Type A RE)/P(RS RE)
B =P(Type B RE)/P(RS RE)
PA=ρA
PB=ρB/ρA
So:
PA= P(Type A RE)/P(RS RE)
PB= P(Type B RE)/ P(Type A RE)
B / A
PB
One
0
1
2
3
1
4/5
3/5
2/5
Two and Four
Antenna Ports
5/4
1
3/4
1/2
The PB configured on eNodeB is the index
of B / A
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RS Power Calculation
For cells whose maximum transmit power per channel in an RRU is 60 W, the following relationships among
bandwidth, reference signal power, and PB apply:
- In a cell with a 20 MHz bandwidth and PA is equal to -3, if PB is set to 0, 1, 2, or 3, the value range of the
corresponding reference signal power is 63 to 193, 70 to 200, 70 to 200, or 70 to 200 (unit: 0.1 dBm)
respectively.
- In a cell with a 20 MHz bandwidth and PA is equal to 0, if PB is set to 0, 1, 2, or 3, the value range of the
corresponding reference signal power is 40 to 170, 40 to 170, 40 to 170, or 40 to 170 (unit: 0.1 dBm)
respectively.
To achieve 100% power usage, the total power of each symbol (1 TTI has 14
symbols) should be same, with PA,PB (-3,1) and (0,0), this target can be realized
HUAWEI TECHNOLOGIES CO., LTD.
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RS Power Calculation
(PA,PB)= (-3,1):
1RB in type A symbol contains 12 type A RE, equals to 6 RS RE;
1RB in type B symbol contains 8 type B RE and 2 RS RE, equals to 6RE;
So the total power of type A symbol is equal to type B symbol, it means
In time domain the RRU transmitting time is the same all the time, can
reach 100 percent usage;
With RRU per port max 60W currently, every symbol contain 100RB*6RS RE=600 RS RE, so RS power=60W/600RS RE=100mw=20dBm
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