Abstract
In this letter, we propose a two-hop orthogonal frequency-division multiplexing with index modulation (OFDM-IM) system, which is assisted by multiple relays and employs multi-carrier relay selection to enhance the system reliability. In particular, two commonly used multi-carrier relay selection schemes are considered, i.e., bulk and per-subcarrier relay selections, and the decode-and-forward relaying is adopted as the forwarding protocol for the proposed system. The analysis of average outage probability of the proposed system is given in closed form and substantiated by numerical results generated by Monte Carlo simulations. By the analytical and numerical results provided, we can observe that the full diversity (equal to the number of relays) can be achieved by applying both bulk and per-subcarrier relay selections in two-hop OFDM-IM systems.
Highlights
C ONVENTIONALLY, amplitude and phase modulation (APM) scheme, e.g., M -ary phase-shift keying (PSK) and M -ary quadrature amplitude modulation (QAM), is applied in communication systems to map a sequence of information bits to a constellation symbol, which has a unique amplitude and phase
We can vary the numbers of relays and subcarriers NR and NS to explore the relation between Pt/N0 and the outage probability
The most efficient approach to enhance the reliability of two-hop orthogonal frequencydivision multiplexing (OFDM) with index modulation (OFDM-IM) systems would be to increase the number of relays NR
Summary
C ONVENTIONALLY, amplitude and phase modulation (APM) scheme, e.g., M -ary phase-shift keying (PSK) and M -ary quadrature amplitude modulation (QAM), is applied in communication systems to map a sequence of information bits to a constellation symbol, which has a unique amplitude and phase. We formulate the power allocation problem for the adaptive OFDM-IM scheme in twohop relay networks and obtain a suboptimal solution based on the Karush-Kuhn-Tucker (KKT) conditions [8]. This contribution significantly extends the work in [7], [8], which focused on the case where there exists only one relay. The DF relaying protocol is adopted at all relays and two commonly used multicarrier relay selection schemes, i.e. bulk and per-subcarrier relay selections are considered in this paper Based on these considerations, we propose a new diversity technique for twohop OFDM-IM in the spatial domain, which is provided by multi-carrier relay selection.
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