Energy Efficient Cooperative Broadcasting in Wireless Networks

Minimizing the total transmission power is one of the main objectives of efficient broadcast algorithms in wireless networks, where all nodes are powered by battery with limited energy supply. Cooperative transmission is an important way to make full use of the space diversity and can save the transmission power significantly, especially in the wireless broadcast transmission, where the nodes can accumulate the overheard information. In this paper, firstly a centralized cooperative broadcast algorithm, which permits multiple nodes to cooperate in transmitting the broadcast message, is proposed to save the total transmission power. Considering that the centralized algorithm requiring a global knowledge of the networks is impractical in large wireless networks, the distributed version of the centralized algorithm requiring only 1-hop neighborhood information is proposed under the assumption that limited frequency band is available. The distributed algorithm combines the physical (PHY) and medium-access-control (MAC) layer mechanisms to reach all the nodes in a cooperative way. Though the proposed distributed algorithm is inferior to the centralized algorithm in terms of total transmission power, it takes less resource to broadcast than the centralized algorithms. Simulation results show that both the centralized algorithm and distributed algorithm can get a better performance than the existing broadcast algorithms. Furthermore, the distributed algorithm can achieve the total transmission power close to the centralized algorithm.