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:
- NB-IoT (SARA N2 Series)
- GSM (SARA G3 Series)
- 3G (SARA U2 Series)
- LTE Cat 1 (LARA R2 Series)
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.
- 1 transmission per minute: T_total = 60 sec
- 1 transmission per hour: T_total = 3600 sec
- 1 transmission per day: T_total = 86400 sec
- 1 transmission per week: T_total =604800 sec
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).
| Mode | Condition | PTx | Current_Consumption of IoT module |
|---|---|---|---|
| Deep-sleep mode | Averaged current over a 10-second period | - | 3 µA |
| Active mode | Averaged current over a 10-second period | - | 6 mA |
| Rx-mode | Averaged current over a 10-second period | - | 46 mA |
| Tx-mode | All Averaged current over a 2-second period | -40 dBm -7 dBm +3 dBm +13 dBm 23 dBm | 74 mA 75 mA 78 mA 100 mA 220 mA |
The power consumption per single data transmission (10 sec):
T_Tx - Transmit Timer (AT+NUESTATS: "RADIO","TX_time") difference between two transmissions
T_Rx - Receive Timer (AT+NUESTATS: "RADIO","RX_time") difference between two transmissions
Timer are averaged over 60 sec. With one data transmission during that time.
P_Tx - Transit Power (AT+NUESTATS: "RADIO","TX_Power")
NB1_Power_Consumption_1min [Ws] = 3,6 [V] *( Current_Consumption_Tx (P_Tx ) [A] * T_Tx [sec] + Current_Consumption_Rx * T_Rx [sec]+ Current_Consumption_DeepSleep *(60 sec - T_Tx [sec]-T_Rx [sec]))
NB1_Power_Consumption_1h [Ws] = 3,6 [V] * (Current_Consumption_Tx (P_Tx ) [A] * T_Tx [sec] + Current_Consumption_Rx * T_Rx [sec]+ Current_Consumption_DeepSleep *(3600 sec - T_Tx [sec]-T_Rx [sec]))
NB1_Power_Consumption_1day [Ws] = 3,6 [V] *( Current_Consumption_Tx (P_Tx ) [A] * T_Tx [sec] + Current_Consumption_Rx * T_Rx [sec]+ Current_Consumption_DeepSleep *(86400 sec - T_Tx [sec]-T_Rx [sec]))
NB1_Power_Consumption_1week [Ws] = 3,6 [V] *( Current_Consumption_Tx (P_Tx ) [A] * T_Tx [sec] + Current_Consumption_Rx * T_Rx [sec]+ Current_Consumption_DeepSleep *(604800 sec - T_Tx [sec]-T_Rx [sec]))
This follows the assumption that the power consumption of the modem in the "Active Mode" can be neglected, since it is rather small compared to the Power consumption in TX-Mode.
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).
| Mode | Condition | PTx | Current_Consumption of IoT module |
|---|---|---|---|
| Idle mode | Averaged current over a 10-second period | - | 4 mA |
| Active mode | Averaged current over a 10-second period | - | 4,7 mA |
| Connected-mode | All Averaged current over a 2-second period | 32 dBm | 250 mA |
The power consumption per single data transmission (10 sec), single tone transmission (9,6kbit/s),
T_Tx - Transmit Time 0,577 msec
T_Rx - Receive Time 1,154 msec
T_active - Active Time 2,884 msec
Power Consumption for data transmission:
T_Data - Time needed for transmission of total_TX_bytes
T_Data = total_TX_bytes * 8 / 9,6 kbit
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]
GSM_Power_Consumption_1h [Ws] = Power_Consumption_Data + 3,8 [V] * (3600 sec -T_Data [sec] )* Current_Consumption_connected [A]
GSM_Power_Consumption_1day [Ws] = Power_Consumption_Data + 3,8 [V] * (86400 sec -T_Data [sec] )* Current_Consumption_connected [A]
GSM_Power_Consumption_1week [Ws] = Power_Consumption_Data + 3,8 [V] * (604800 sec -T_Data [sec] )* Current_Consumption_connected [A]
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)
| Mode | Condition | PTx | Current_Consumption of IoT module |
|---|---|---|---|
| 3G Cyclic Idle/Active-Mode (Power Saving enabled) | Averaged current over a 10 minute period, DRX = 930, +UPSV=2 or 3, USB disconnected | - | 0,9mA |
| UMTS Connected Mode (Tx / Rx call enabled) | Averaged current over a 10 second period, 12.2 kbit/s UL, 12.2 kbit/s DL | min 0 dBm 12 dBm 18 dBm max dBm | 115 mA 135 mA 190 mA 325 mA 565 mA |
T_Data = total_TX_bytes * 8 / 5.760 kbit/s
P_Tx - Transit Power (AT+NUESTATS: "RADIO","TX_Power")
Power_Consumption_Data = 3,8 [V] * T_Data [sec] *Current_Consumption_Connected (P_Tx ) [A]
Assumption: The Modem is not switched-off or not sent into the idle mode, but stay in the active mode as long as it does not transmits data.
3G_Power_Consumption_1min [Ws] = Power_Consumption_Data + 3,8 [V] * (60 sec -T_Data [sec] )* Current_Consumption_cyclic_Idle [A]
3G_Power_Consumption_1h [Ws] = Power_Consumption_Data + 3,8 [V] * (3600 sec -T_Data [sec] )* Current_Consumption_cyclic_Idle [A]
3G_Power_Consumption_1day [Ws] = Power_Consumption_Data + 3,8 [V] * (86400 sec -T_Data [sec] )* Current_Consumption_cyclic_Idle [A]
3G_Power_Consumption_1week [Ws] = Power_Consumption_Data + 3,8 [V] * (604800 sec -T_Data [sec] )* Current_Consumption_cyclic_Idle [A]
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)
| Mode | Condition | PTx | Current_Consumption of IoT module |
|---|---|---|---|
| Cyclic Idle/Active-Mode (Power Saving enabled) | Averaged current value over a 10-minute period, | - | 1,4mA |
| Tx-mode | Averaged current value over a 10-second period | min 0 dBm 12 dBm 18 dBm max dBm | 185 mA 200 mA 245 mA 365 mA 540 mA |
T_Data = total_TX_bytes * 8 / 5.000 kbit/s
P_Tx - Transit Power (AT+NUESTATS: "RADIO","TX_Power")
Power_Consumption_Data = 3,8 [V] * T_Data [sec] *Current_Consumption_TX_Mode (P_Tx ) [A]
Assumption: The Modem is not switched-off or not sent into the idle mode, but stay in the active mode as long as it does not transmits data.
4G_Power_Consumption_1min [Ws] = Power_Consumption_Data + 3,8 [V] * (60 sec -T_Data [sec] )* Current_Consumption_cyclic_Idle [A]
4G_Power_Consumption_1h [Ws] = Power_Consumption_Data + 3,8 [V] * (3600 sec -T_Data [sec] )* Current_Consumption_cyclic_Idle [A]
4G_Power_Consumption_1day [Ws] = Power_Consumption_Data + 3,8 [V] * (86400 sec -T_Data [sec] )* Current_Consumption_cyclic_Idle [A]
4G_Power_Consumption_1week [Ws] = Power_Consumption_Data + 3,8 [V] * (604800 sec -T_Data [sec] )* Current_Consumption_cyclic_Idle [A]
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.
XXX_Battery_Life_Time_1min [year] = 3600 * Capacity_AAA [Wh] / (XXX_Power_Consumption [Ws]* 525600)
XXX_Battery_Life_Time_1h [year] = 3600 * Capacity_AAA [Wh] / (XXX_Power_Consumption [Ws] * 8760)
XXX_Battery_Life_Time_1day [year] = 3600 * Capacity_AAA [Wh] / (XXX_Power_Consumption [Ws] * 365)
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:
- Latency of the Network (Ping to the APN)
- Latency of the Cloud (Acknowledgment of the Cloud Server)