Integration Manual

SARA-R4/N4 series - System Integration Manual
UBX-16029218 - R11 System description Page 24 of 157
1.5.1.2 VCC current consumption in LTE connected mode
During an LTE connection, the SARA-R4/N4 series modules transmit and receive in half duplex mode.
The current consumption depends on output RF power, which is always regulated by the network (the
current base station) sending power control commands to the module. These power control commands are
logically divided into a slot of 0.5 ms (time length of one Resource Block), thus the rate of power change
can reach a maximum rate of 2 kHz.
Figure 4 shows an example of SARA-R4/N4 series modules’ current consumption profile versus time in
connected mode: transmission is enabled for one sub-frame (1 ms) according to LTE Category M1 half-
duplex connected mode.
Detailed current consumption values can be found in the SARA-R4/N4 series Data Sheet [1].
Time
[ms]
Current [mA]
0
300
200
100
500
400
Current consumption value
depends on TX power and
act ual ant enna load
1 Slot
1 Resource Block
(0.5 ms)
1 LTE Radio Fram e
(10 m s)
1 Slot
1 Resource Block
(0.5 ms)
1 LTE Radio Fram e
(10 m s)
Figure 4: VCC current consumption profile versus time during LTE Cat M1 half-duplex connection
1.5.1.3 VCC current consumption in 2G connected mode
When a 2G call is established, the VCC consumption is determined by the current consumption profile
typical of the 2G transmitting and receiving bursts.
The current consumption peak during a transmission slot is strictly dependent on the transmitted power,
which is regulated by the network. The transmitted power in the transmit slot is also the more relevant
factor for determining the average current consumption.
If the module is transmitting in 2G single-slot mode in the 850 or 900 MHz bands at the maximum RF
power control level (approximately 2 W or 33 dBm in the Tx slot/burst), then the current consumption can
reach a high peak / pulse (see the SARA-R4/N4 series Data Sheet [1]) for 576.9 µs (width of the transmit