Uplink Power Control in Relay Enhanced Lte Advanced Networks

In April 2008, the 3 rd Generation Partnership Project (3GPP) agreed on its candidate technology named as LTE Advanced (LTE-A) to fulfill the requirements of IMT Advanced which was recently defined by ITU. According to the requirements, LTE-A is expected to provide high data rates while maintaining coverage proportional to LTE Release 8. In this thesis, a novel way of implementing the relaying concept is proposed to satisfy the tough demands of LTE-A as relays improve cell edge capacity, lower OPEX, reduce backhaul costs and enhance network topology. This thesis discusses the positive and negative aspects of deployment of relays within the LTE framework and evaluates the performance of relay enhanced cells (REC). Moreover, the new cell edges introduced by relay nodes (RN) will lead to severe intra-cell and inter-cell interference, in particular, when a high number of RNs are deployed in the cell with reuse one. Power control (PC) becomes an important method for mitigating this interference as well as increasing the cell edge and system capacity in the uplink (UL). Hence, the standardized 3GPP LTE UL PC scheme should be investigated in relay based deployment. This thesis mainly examines the UL in RECs within the LTE framework in terms of LTE UL PC scheme that considers a fractional PC in which performance enhancement is aimed for the cell center users by inducing an acceptable level of inter-cell interference. Furthermore, the thesis includes an investigation of parameter configuration and performance evaluation of the LTE UL PC in Macro cell scenarios. Subsequently, the 3GPP's approved UL PC scheme for LTE is applied both at eNBs and RNs in relay based deployment and performance evaluation is given. Parameter optimization and transmit power setup are examined to achieve optimal performance in REC scenarios. PREFACE This Master's Thesis presents the work that was carried out under the supervision of Prof. Jyri Hämäläinen from Helsinki University of Technology (HUT) and under the instruction of Doc. Simone Redana from Nokia Siemens Networks (NSN). The thesis work was performed at NSN premises in Munich / Germany