Cooperative Communication

CHAPTER 2

LITERATURE REVIEW

2.1 Literature Review

Elza Erkip, in cooperative communication in wireless system explained about the ‘overheard signals’ of the neighboring nodes. In this paper, the description of the information of theoretical model has been proposed and studied about the outage probabilities and gain rate regions that diversity has allowed. [1]

Arnab Chakrabarti, in the paper, titled “Cooperative Communication: Fundamental limits and Practical implementation” proposed the gains for user cooperation in the communication. The paper proposed that the three or more terminal relay channel is well suited for cooperative communication. Also results on Gaussian channels are implemented and discussed in the paper. [2]

F. M.

Jayaweera, has proposed wireless cooperative communication based on virtual multiple input multiple output (MIMO).He derived energy and delayed efficiencies of the suggested system. He compared the parameters of virtual MIMO sensor network to that of traditional SISO networks and found that virtual MIMO network offers more energy savings and less delay efficiencies. [5]

Shiou-Hung Chen, studied the routing techniques in fading channels and derived the strategies for power optimization in cooperative communication and provided the near optimal algorithm in the paper. The author found that routing in multi hop cooperative communication is more energy efficient in practical manner. The gain of multi hoping is more than that of direct transmission over practical values of path loss. [6]

Pei Liu, in the paper Showed that cooperative communication exists at different protocols and layers and discussed about the optimization and design for cross layer. The author has explored the cooperation at the layer 1 and 2 of the OSI model and then he proposed the new protocol for IEEE 802.11 at the MAC layer which named “CoopMAC”. This protocol enables the diversity capacity which combines various destinations with the transmitter.

Therefore to optimize, genetic algorithm (GA) appeared as a conflicting optimization algorithm for a wide range of complex cost functions. The applications of GAs have put large potential in solving complex problems related to the designing of antenna optimization and have become an active area for research. The paper presented various GA applications for adaptive antennas. Also the paper demonstrated the solution using GA to control the characteristics of antenna adaptively. The author demonstrated the example which shows the efficiency of GA to place nulls quickly in the side lobes in the directions of the interfering signals by reducing the total output power. The paper shows reviews about the adaptive linear antenna array optimization. The chief issues involved during optimization process are: Problems of nulls symmetry about the main beam, complexity, slower GA convergence, and cost for designing null steering. The methods of null steering includes the complex weights (the amplitude and phase) controlling and the excitation (amplitude only and phase-only), and the element position only are considered extensively in the above literature. The paper concludes that by allowing little changes on the evaluation function is sufficient to fix many assumptions and necessities of different problems.