Todays, various internet services and portable handheld devices have increased demands for wireless internet services. Since there are many demands for high data rate services in recent years, wireless technology have developed from first generation (audio) to present complex high data rate generation. The standards for 4th generation of mobile networks have been designed in order to provide high data rate for mobile users. Besides, OFDM multicarrier technique has been used frequently as a method for earning high data rates. This technique can overcome major problems such as frequency selective fading channel and inter-symbol interference (ISI) because of its nature. Furthermore relaying transmission methods have attracted many attentions recently therefore relay technology in combination with OFDM is considered as an effective approach in fourth generation mobile networks. In these networks, there are some important resources such as power, subcarriers which their allocation method to users has very important effect on overall network performance and each allocation algorithm has its own advantages and disadvantages. In this thesis, we investigate performance of different relaying schemes in a two-way multiuser single-relay network (with Amplify and Forward protocol in relays) combined with OFDMA method for data transmission. Essentially our goal is to maximize overall network achievable data rate considering limited powers on each network node. There are four different two-way relaying scenarios depends on different number of time phases in data transmission and existence of direct link. For each relaying scenario, at first we introduce resource allocation problem and since finding optimum solution is very complex, a new suboptimum subcarrier allocation method is presented which provide better performance results compared to the previous presented suboptimum method in all 2-phase, 3-phase and 4-phase scenarios. Keywords: Resource allocation, Amplify and Forward (AF), OFDMA, Two-way relaying , Multiuser
