Impact of variable transmission range in all-wireless networks

In this thesis, we propose three distributed algorithms for self-adjusting the transmission range of nodes in wireless network. The objective is to vary the transmission radii of selective sensor nodes to lower the energy spent in broadcasting or the diameter. The sensor nodes start arbitrarily with different transmission ranges. The nodes positions are fixed, and can adjust the transmission power. However, increasing the transmission power to reach more nodes may consume more energy. So, the goal is to reduce the transmission power (i.e., save energy) without reducing the reachability (in terms of the number of nodes); We propose two algorithms that increase the transmission range of nodes. Increasing the transmission range of selective nodes will lower the diameter but increase the total energy. The proposed algorithm computes the ratio of the increase in transmission range to the increase in number of nodes of every sensor node. The node with the smallest ratio will be selected to increase its transmission range; The third algorithm decreases the transmission range of the nodes. Decreasing the transmission range will lower the total energy but increase the diameter of the network. Ratio of decrease in the transmission range to the decrease in the number of nodes is calculated for every node, and the node with the highest ratio is selected to decrease its transmission range; A larger diameter implies a higher chance of interference between the neighboring nodes. When two nodes are in not in the communication range of each other, there is a probability that both the nodes send the packets to each other at the same time using the same channel. The nodes will not be able to decide by themselves, hence a collision will occur. This is known as hidden terminal problem. A lower diameter implies a higher chance of message duplication. Same message will be received twice; All three algorithms will be simulated and compared based on the experimental results