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The performance tab shows different a comparison of different cellular standards that could be used for IoT connectivity, NB-IoT, GSM, 3G (UMTS) and LTE. The basis for the comparison are cellular modems from ublox:

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The following screenshot shows the performance tab of the NB|EASY software.

Power Consumption

The calculation of the power consumption for different cellular standards are described in the following sections. We calculate the power consumption for the transmission of a single data packet.

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The power consumption is then given as percentage of the LTE power consumption.

NB-IoT

The basis of the power consumption calculation is the specification of the SARA 211 Module (SARA-N2 DataSheet).

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Assumption: The model calculates the power from TX & RX timing counters. Therefore it takes into account that the modem switches into RX after the TAU-period. The power consumption will therefore depend on the actual setting for transmission. The initial cell search and attachment is not considered. For power consumption  for transmissions less often than once per minute, the power consumption of regular RX-periods after TAU is not considered. It is assumed that the modem is in deep sleep rather than in the RX-status occasionally.


GSM

The basis of the power consumption calculation is the specification of the SARA G3 Module (SARA G3 Series).

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Power_Consumption_Data = 3,8  [V] * T_Data [sec] * Current_Consumption_connected [A]

(the TX power is not considered, since there is no power control in GSM)

GSM_Power_Consumption_1min  [Ws]  = Power_Consumption_Data  + 3,8  [V] * (60 sec -T_Data [sec] )* Current_Consumption_connected [A] 

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Assumption: The Modem is not switched-off or not sent into the idle mode, but stay in the active mode (attached) as long as it does not transmits data. The initial cell searattachment is not considered.

3G

The basis of the power consumption calculation is the specification of the SARA U260 (Band 8) Module  (SARA U2 Series)

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Assumption: The Modem is not switched-off or not sent into the idle mode, but stay in the Cyclic Idle/Active-Mode (attached) as long as it does not transmits data. The initial cell searattachment is not considered.

LTE

The basis of the power consumption calculation is the specification of the LARA R2 (LARA R2 Series)

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Assumption: The Modem is not switched-off or not sent into the idle mode, but stay in the Cyclic Idle/Active-Mode (attached) as long as it does not transmits data.The initial cell searattachment is not considered.

Battery Lifetime 

We assume a standard battery pack of three AAA bateries with Capacity_AAA  = 1.8Wh.

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XXX_Battery_Life_Time_1week [year] = 3600 * Capacity_AAA  [Wh] / (XXX_Power_Consumption  [Ws] * 52)


Data Rate (Uplink)

Only the NB-IoT data Rate is measured. For the other Standards we use typical values.

  • NB-IoT:  Data_Rate = total_TX_bytes * 8 * TX_time
  • GSM: 9,6 kbit/s
  • 3G: 5.760 kbit/s
  • LTE (Cat 1): 5.000 kbit/s

LATENCY

Two latencies are displayed:

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