Adaptive Resource Allocation Strategies for Dynamic Heterogeneous Traffic in Td-cdma/Tdd Systems

The purpose of this study was to investigate the co-channel interference present in TD-CDMA/TDD systems and TDMA/TDD systems and propose methods to avoid the co-channel interference. Time Slot Opposing algorithm which avoids co-channel interference in TD-CDMA/D-TDD system is reviewed as part of background study. The interference scenarios in TDMA/D-TDD systems are then studied and methods to avoid co-channel interference are proposed. The algorithms are then tested using real Internet data traffic to obtain a realistic analysis. Based on the background research, an extended Max {SIR} algorithm is proposed to avoid co-channel interference in TDMA/D-TDD systems. This algorithm is a centralized dynamic channel allocation algorithm that uses information from all the cells in the system to avoid co-channel interference and increase the signal power-to-interference power outage probability ratio. The proposed algorithm is then applied to a TDMA/D-TDD system that have subscribers grouped based on priority. As a last step of the research, traffic in TDMA/D-TDD systems is modeled using the ON-OFF traffic modeling and the Max {SIR} algorithm is applied. The results obtained using ON-OFF traffic modeling matched with the results obtained using analytical simulations.School of Electrical & Computer Engineerin

Femtocell deployment; next generation in cellular systems

The final Bachelor’s Thesis that is shown below has such a final purpose of giving an overview of the inclusion of the so-called Femtocells (or Home Node B) in the current cellular systems. The main objective is to give a clear but simple idea about the concepts of Femtocells, as well as to explain the benefits and disadvantages of the mass uses of these services both for consumers and associated companies with this phenomenon. In this text it is also possible to find a brief review of wireless technologies throughout the history of telecommunications, as well as an introduction to the more current wireless technologies, with a special interest in the concept of cellular systems. In the last chapter a simple mathematical explanation of the key issue of interference between Femtocells and macrocellular networks is presented, with a brief argument about possible solutions

Medium access control protocol design for wireless communications and networks review

Medium access control (MAC) protocol design plays a crucial role to increase the performance of wireless communications and networks. The channel access mechanism is provided by MAC layer to share the medium by multiple stations. Different types of wireless networks have different design requirements such as throughput, delay, power consumption, fairness, reliability, and network density, therefore, MAC protocol for these networks must satisfy their requirements. In this work, we proposed two multiplexing methods for modern wireless networks: Massive multiple-input-multiple-output (MIMO) and power domain non-orthogonal multiple access (PD-NOMA). The first research method namely Massive MIMO uses a massive number of antenna elements to improve both spectral efficiency and energy efficiency. On the other hand, the second research method (PD-NOMA) allows multiple non-orthogonal signals to share the same orthogonal resources by allocating different power level for each station. PD-NOMA has a better spectral efficiency over the orthogonal multiple access methods. A review of previous works regarding the MAC design for different wireless networks is classified based on different categories. The main contribution of this research work is to show the importance of the MAC design with added optimal functionalities to improve the spectral and energy efficiencies of the wireless networks