Research On Large-scale Antenna System With Multiple Antennas Users

Wireless communication technologies have entered into a stage of rapid development,High quality of communications and high rate of wireless data transmission are required urgently.Massive MIMO transmission technology,its high spectral efficiency and high power efficiency make it become the key technologies of the next generation of wireless communication systems.Massive MIMO technology allows to transmit or receive multiple spatial data streams at the same time by installing multiple antennas at the transmitter and/or receiver of the communication system.Massive MIMO becomes the technology which is used to improve performance or capacity of resources,to make a number of spatial data links sharing time and frequency band transmission.Massive Multiple-Input,Multiple-Output(MIMO)systems are attracting more and more attentions due to their advantages in greatly increasing the system capacity and improving the quality of wireless links.In the existing studies,it is usually considered that users in the system are with single antenna.On the other hand,with the continuous development of technology,it is possible to install multiple antennas on the user side.This thesis analyzes and studies a massive MIMO system with users being equipped with two antennas.For the multi-cell,massive MIMO uplink system,each base station is equipped with M antennas and services K users at the same time and the same frequency band.Assume that each user is equipped with two antennas.In this thesis,firstly,to maxing benefits of linear decodes such as,Zero-Forcing(ZF)or Minimal Mean-square Error(MMSE)decodes,a designing criterion of the space time block codes is given for the system.Secondly,the lower bounds of the achievable uplink rates under conditions that the system adopts the ZF,MMSE decoding methods and the designed space time block codes are derived.The simulation results show that the achievable uplink rate of the system with two-antenna users is much higher than that of the existing multi-cell,massive MIMO systems with single-antenna users.Finally,Under the condition of limited received power,this thesis deduces that the approximate value of the user achievable uplink rate when the number of the BS antennas,M,goes to infinity.Finally,for the single-cell uplink system with the ZF or MMSE decoding method,this thesis also deduces the pair-wise error probability(PEP)formulas,and upper and lower bounds of the PEP and the analytic expressions of the approximate estimations are obtained.The simulation results verify the correctness of the formulas above.Also,at the same bit rate transmission,simulations of the bit error rate of the systems with the single-antenna users and with the two-antenna user are implemented.Results show that the system with the two-antenna users has much lower error probability than the system with the single-antenna users.