Research On Energy Efficient Relay Transmission Techniques In Cooperative Communication System

Nowadays, resource has become increasingly scarce while people’s demand is increasing and the energy consumption growth rapid, so how to make fully use of resources in the limited energy is a hot topic today. What is worse, the same problem occurs in the communication system. The definition of energy efficiency just can meet the demand, which is defined as the number of bits per unit of energy that can be transmitted, i.e., the amount of information can be transmitted in the unit power. In other words, to make it represents best means the make fully use of energy. The research of relay cooperative communication system has also attracted many attentions, which uses the relay nodes to form a virtual MIMO for signal transmission. It has many excellent features of MIMO system. This thesis aims to combination these two research fields together, proposed the optimal relay selection on the basis of energy efficiency, studied on energy efficiency issues of the two-way relay system with the rate fairness, the former is mainly analysis the energy efficiency of one-way relay transmission process, and according to the constraints selected reliable set of nodes, and then select a optimal node from the set for the signal transmission. and the method result is verified by numerical simulation. In conclusion, the method can make the energy efficiency optimization and has no effect on the spectral efficiency; the latter is mainly considered the energy efficiency in the rate of two kinds of circumstances which are equal and unequal with bidirectional relay transmission system, and the optimal choice for the relay nodes, also discusses the balance between energy efficiency and spectral efficiency. In finally, using the same simulation to obtain the conclusions: when designing the system to consider the balance between the energy efficiency and spectral efficiency, and through compare the size of equal to the rate and rate ranging from the sum of two SNR, when the present is smaller than the latter, the energy efficiency is optimal with the rate fairness, at this time also can convenient to ajust the transmission power at the transimitting terminal according to the actual demand.