Enhancement of energy efficiency in massive MIMO network using superimposed pilots

摘要

Fifth generation wireless communication intends to provide extensive improvement in energy efficiency of long-term evolution-advanced network. This feature can be accomplished by incorporating spatial multiplexing which involves base station antenna in large number known as massive multiple input multiple output system. The potential constraint of this system is pilot contamination which introduces interference instigated by reusing pilots from neighbor cells in a multicell system. The pilot contamination can be reduced by varying the length of pilot sequences. The conventional system known as regular pilot uses data and pilot symbols disjointly for transmission. The proposed system known as superimposed pilots overlays the pilot and data symbols for transmission. This superimposed pilot allows to use pilot symbols in an extended duration and in turn reduces the pilot contamination. To analyze the performance of both the pilots, precoding schemes like maximal ratio combing and zero forcing is used. To enhance the performance further antenna selection algorithm has been implemented along with the precoding scheme. This algorithm will choose the antennas with threshold level for maximization of energy efficiency. The simulation results will prove that superimposed pilot with antenna selection algorithm will archive high average rate and energy efficiency than the conventional random pilots.