# Spectrum Based Power Management for Congested IoT Networks
## 5 Test Results and Analysis
### Idle State or Sleep State  
The idle or sleep state is when the IoT device is only listening. Figure 5 shows both the connected and idle states. Where T_idle represents release phase of connected state.  
During the testing of our experiment, no matter how many packets congested the network, the TX/RX process consumes same amount of power.  
Figure 6 shows the experimental current traces for a connected state of IoT device for 100 healthcare data packets with load of 20 byte each. The high current consumption is also recorded during these intervals in which the device is actively transmitting, receiving or listing the channel for possible messages from the CN.  
Figure 5: Display of results.  
Figure 6: Connected state power consumption.  
It is clear that the power consumption of an IoT device in connected state depends on the time interval spent during each TX/RX. Which is highly affected by the spectrum management mechanism. In other words, if we minimize the TX/RX delay by effective spectrum management using FREDEVPLA the overall performance of our network is better and less energy consuming. However, as the TX/RX interval of IoT device increases, its power consumption also grows to some degree due to the increased network congestion.  
Every data transmission is followed by a reception interval where the IoT device waits for possible acknowledgement packets from its CN. In the current traces, the data Tx are preceded and followed by peaks of current consumption, as illustrated in Figure 7. Such peaks are recorded during control signaling traffic. The actual data transmission causes a lower peak and lasts longer. So, adding more controls at the IoT device level to manage spectrum means increase in the average power consumption. That is why we do not recommend adding any channel control configurations at an IoT device level. More than its simplicity, managing configuration for IoT from FREDEVPLA minimize challenges of memory usage, possess speed, and resource management.  
The power consumption with our proposed method is always efficient than the normal/standard method minimum by 30% as shown in result comparison part. This is due to our proposed spectrum management scheme always performed separately at the FREDEVPLA level in condition where there is high traffic load.  
The plot in Figure 8 show experimental current traces with periodic paging/listing for idle state.  
Here it is important to mention that the majority of IoT device's lifetime is spent on idle state and note that this mode do not have a specific time duration, thus we present  
Figure 8: Sleep status consumption.  
Figure 7: Data and control power consumption.  
the power consumption rather than the energy. Even if the idea behind idle state is to save power, most of the IoT devices do paging for short time intervals during this time to check any waiting messages. The device exits the idle state when the configured time expires or when new CN data are waiting. Regardless of the configured time interval, paging process consumes constant amount of power every single step, seen in Figure 9.