Combining relaying and base station coordination for improving cell-edge multi-user performance in 3GPP LTE-Advanced networks

Abstract

The emphasis of this thesis work is placed on improving cell-edge multi-user performance in 3GPP LTE-Advanced networks by utilizing relaying and base station coordination technologies. Relaying is a technology for enhancing the transmissions between two locations on a radio path and base station coordination is a multi-cell processing technology towards mitigating the inter-cell interference. In this report, we first study the capacity behavior of relaying. Two forward strategies: Amplify-and-forward (AF) and Decode-and-forward (DF), are modeled and compared. A new full duplex (FDX) operation mode of relaying is discussed, as well as a relay network with a multi-antenna receiver. Results show that FDX relaying outperforms half duplex (HDX) relaying, DF relaying has better performance than AF relaying under the condition of an ideal relay link (RL) and a multi-antenna receiver gains more from relaying than a single-antenna receiver. Then, we apply the pre-coding on the coordinated evolved Node B (eNB) to realize simultaneous multi-user transmissions on the same frequency band. Designs of the pre-coding matrix are investigated and results show that zero-forcing (ZF) pre-coding of base station coordination reaches significant capacity enhancement in the case of a relatively high signal-to-noise-ratio (SNR). Finally, we propose a novel combination transmission scheme which integrates a shared relay node (RN) and coordinated eNBs in order to achieve higher multi-user sum-rate capacity. We show that the advantages of this combination scheme compared with applying each technology separately can be expected in most cases and it turns out to be a good improvement of the cell-edge multi-user performance.