Research On Non-ideal Two-way AF Relaying System And Full-duplex Relaying System

Cooperative relaying is a multiple-input-multiple-output(MIMO) system in essence formed by sharing antennas with scattering nodes in geometry, thereby solving the problem of deploying multiple antennas on mobile nodes due to the cost and size limitation. It has been a hot research topic in academic and been widely concerned by the industry due to its strong abilities to expanding communication coverage area, combating channel fading and improving the system capacity. Moreover, it has been adopted in several international standards, such as 3GPP LTE-A and IEEE 802.16. This thesis mainly concentrates on amplify-and-forward two-way relay(TWR-AF) system and full-duplex relay(FDR) system, with the common being exchange information within two time slots compared with conventional owe-way relay system consuming four time slots. The main work and contributions are as follows:Firstly, consider the TWR-AF system in the presence of the imperfect channel state information(ICSI) and the asymmetric data rate requirements in real wireless communication system. The exact expressions of overall outage probability(OOP) and a very tight lower bound are derived by dividing the asymmetric factor into three categories. In order to gain more insights into the impact of system parameters on OOP, an asymptotic expression for OOP is derived at high SNR regime, which shows that due to the presence of ICSI, OOP is statured and there is an errors floor(EF) phenomenon. An optimal relay location scheme is proposed aiming to optimizing OOP and a closed form expression is obtained over independent and identical distributed Nakagami-m fading channels. The conclusion and expressions derived is general and universal and the simulation results show the usefulness of the derived formula and the correctness of theoretical analysis.Secondly, considering a TWR-AF system in the presence of I and Q signals imbalance(IQI) at relay, after a simple IQI compensation, an analytical expression for individual OP and asymptotic expression are derived. The reason resulting to SINR ceiling effect is analyzed. Then, an lower bound for OOP and the achievable sum ergodic capacity expressions are derived, which are shown tight at whole SNR range. The derivedexpressions and analysis demonstrate that without IQI compensation, OOP and ergodic capacity achieve an ceiling effect with its values depended on system parameters, however, the ceiling effect can be eliminated with IQI compensation. As an extension of the case, considering a variety of the hardware impairments, the corresponding TWR-AF system is modeled and we derive the accurate closed-form expressions and asymptotic expression for individual OP, which has a valuable guidelines in practical system design. The simulation results show the accuracy of the theoretical analysis and the effectiveness of the OPA scheme.Finally, consider the decode-and-forward-based full duplex relay(FDR-DF) system. There always exists a loop interference(LI) from the transmitting antenna to receiving antenna and model it as a fading channel. Exact analytical expressions of OP are deduced with the single relay systems and opportunistic relay selection(ORS) based multiple relays system. In order to maximize the ergodic capacity of the considered system, a power allocation scheme based on instantaneous CSI is proposed under two different power constraints, and compared with the equal power allocation scheme. Moreover, the influence of LI on system performance is studied. The valuable conclusions are drawn that the OP of FDR system is more optimal than that of HDR system in scenarios of lower transmit power and higher data rate requirement. At last, the derived OP expression and power allocation scheme are verified by numerical results and computer simulations.