Spectrally Efficient Incremental Relaying for Coverage Expansion in Cellular Networks with Heterogeneous Path Loss Conditions

In this paper we propose a cooperative scheme in which fixed relays operate with a higher spectral efficiency than the source. The relay transmits times faster than the source with times the spectral efficiency, reducing the loss inherent to the orthogonal cooperation. We assume a large scale path loss model which is capable of handling with heterogeneous conditions between the nodes of the network: the source, the relay and the base-station antennas can be at different heights. Our results show that the proposed scheme consumes less energy while achieving up to 3 dB of gain, in terms of throughput, when compared to the baseline cooperative scheme. In addition, a coverage area analysis shows that the proposed scheme increases considerably the cell area when compared to the non-cooperative transmission and to the baseline cooperative scheme. Finally, we show that the proposed scheme, with a single relay, outperforms in the high signal to noise ratio region the regular cooperative scheme using multiple relays.