Week 3: Improvement of protocols

Last week, the coding of two routing protocols (FLOODING & GOSSIPING) were compiled. After discussing with supervisor, the obtained results were right and there were some problems. First, the sink (base station) should be added to the sensor nodes system for collecting whole energy. Secondly, the figure only shows that the energy was consumed and we need to show the increasing of energy for achieving the sustainable operation and extending the lifetime of system.

This week, several parts had been finished.

1.    The values of various parameters were specified. For instance, battery capacity and energy consuming when sensor transmit or receive data packets. There are two equations which are used for calculating the energy.

• §  For transmission of data: E=E(elec) + C(amplification)d², E(elec) is a constant which is communication module, C(amplification) represents amplification constant. The data should be amplified when it is transmitted and d means the distance between two nodes.
• §  When the sensor receiving the data packet, the data need not to be amplified and the energy is only equal to the energy of communication module. Thus the equation is E=E(elec).

2.    The program for optimizing solution based on flooding protocol was coded.

3.    The sink (base station) was fixed and the best position was built.

4.    The lifetime between flooding and optimizing solution based on flooding protocol was compared. For accelerating the run time of program, the size of data packets was enlarged 100 times. Finally, the rough result for optimized solution is 7 days and 60000 seconds, while for flooding, the lifetime is 2 days and 60000 seconds.

The optimizing solution is based on SPIN (sensor protocols for information via negotiation) protocol. When a sensor has data that want to transmitted, it will send a broadcast signal which called ADV to its neighbors, and then the neighbors who has no data can send a signal called REQ back. Final, the node which receive the REQ signal will transmit data packets. In addition, for extending the lifetime of system, there is a judgmental statement of time. If a sensor node of a hop has very low power, this statement will work to calculate the time for another hops without low power node. If the time is less than a specific value, it means that another hop can work and the data packets are transmitted to destination node. In contrast, the hop will work although the node has low power.

For determining the position of sink (base station), a possible method was provided. First, middle point of distribution is determined, which mean the number of node for a hop is minimum. In addition, if there are several middle point node, middle point of distance will be considered. Then the only one distribution node is chose based on the minimum distance between middle distribution nodes and middle distance node. However, the coding of this method had not been compiled successfully. This problem will be solved next week.