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In Fig.6.2, we compare between Hybrid power using MDP harvesting power model and pure AC power for different transition probabilities set which it valid for MDP condition.
In Fig.6.3, we compare between percentages of dropped packets from total transmutation packets for two proposed scenario.
In Fig.6.4, we compare between percentages of wastage energy from total harvesting solar energy in both scenario.
In Fig.6.5, we compare performance first scenario only in power consumption and percentage drop packet for different buffer size.
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Figure.6.2 The power consumption for different size of the buffer
Both scenario shows good performance to minimize AC power usage.
Also the performance of 2nd scenario is little better than 1st scenario.
For high data rate receiving packet, it is expected the performance of 1st scenario will be better than 2nd scenario; trading off between using harvester energy immediately or not will make balanced between AC power consumption and using harvester energy efficiently.
The relationship between buffer size and power consumption is approximately linear;
since we assume the power that it needs to transmit one packet just equals one battery or AC power unit.
Figure.6.3 Percentage of dropped packet for different size of the buffer
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The percentage of dropped packet will decease when the buffer size increase for 1st scenario.
The performance of 1st scenario will improve if the battery states increases for simple case.
The percentage of dropped packet in 2nd scenario equals zero because the data rate of receiving packet is low and the buffer uses any kind of power to transmit packet directly.
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Figure.6.4 Percentage of wastage solar energy for different size of the battery The percentage of wastage energy will decease when the battery size is increased for both scenarios. Moreover, the performance of 2nd scenario is better than 1st scenario.
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2nd scenario uses harvester energy immediately expect when buffer of packet is empty. Figure 6.5 Performance the first scenario in power consumption and percentage drop packets.
Simulation results shows despite of the average saving power consumption of proposed scenario increments more than 50% when buffer size increased, but the power consumption increases, too. By the way, the drop packet percentage is decreased when buffer size increases. Therefore, the best performance of first scenario occurs when the size of the packet buffer is between 5 to 7 packets. However, the best performance of second scenario occurs when the size of the packet buffer is1 packet cause percentage of dropped packet equals zero. Aside, when we compare different features of performance second scenario for different buffer size , the best buffer size will be 3 to 4 packets.
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Chapter 7 Conclusions
• In this thesis, MDP have been studied the problem of minimizing AC power using MDP harvesting power model for WSN.
• Basically, combination AC and battery power (hybrid power) in this model.
Next, the policy controls when to transmit packets to minimize AC power usage.
• The energy harvesting is a key factor for base station energy saving.
• Hybrid Policies are good technique for saving power in all cases.
• Energy saving is important and necessary; a lot of research is in progress to save BS energy.
• Power consumption decrease when using low states probabilities.
• Second scenario gives little better results than first scenario.
• There is no dropped packet in Second Scenario cause the buffer transmit packet immediately using any kind of power.
• The average wastage energy from harvesting in 2nd scenario is better than 1st scenario by 85%.
• The suitable size of the buffer that it will give best performance for first scenario is between 5 to 7 packets. Hence, buffer will make balance between totally power consumption and saving AC power with minimum percentage drop of packets．
• The suitable size of the buffer that it will give best performance for second scenario is between ３ to ４ packets. Hence, buffer will make balance between totally
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power consumption and saving A C power with minimum percentage drop of packets.
Moreover, second scenario used harvesting energy more efficiently with very low percentage of wastage solar energy.
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Future Work
Find nonlinear relationship between packet size and power consumption Energy using harvester more efficiently
Determine more reliable model to use in 4G LTE Save more AC power usage
Optimize Scenario uses only harvester solar energy with multi buffer.
Avoid dropped packet
Minimize wastage solar energy
Optimize Scenario uses only harvester solar energy with buffer.
Avoid dropped packet
Minimize wastage solar energy
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