Goodput-maximizing resource allocation in cognitive Radio BIC-OFDM systems with DF relay selection

Abstract

We propose a novel resource allocation (RA) strategy for a cognitive radio packet-oriented bit-interleaved coded orthogonal frequency division multiplexing (BIC-OFDM) system with decode-and-forward (DF) relays. The aim of the RA is maximizing the goodput (GP) of the source-relay-destination link, which is the number of information bits correctly received at the destination node per unit of time. Therefore, we derive an accurate analytic approximation for this figure of merit, which allows us to find the optimum constellation size, code rate and energy allocation per subcarrier. Further, this expression also serves as a novel relay selection criterion. Finally, we validate the proposed RA method, and compare its performance to capacitymaximizing algorithms through numerical simulations

Adaptive coding and modulation using imperfect CSI in cognitive BIC-OFDM systems

“…By using the statistical approximation for the effective SNR, which we introduced in [21], we now derive an analytical, tractable approximation for the EGP, which we call the approximate EGP (AEGP). In the numerical results, we show that the AEGP is a far more accurate approximation of the EGP, compared to the metrics used in [19,20]. To the authors' knowledge, these works are the first ones which propose to use a practical metric, which takes care of the imperfect CSI, for the optimization of the transmission parameters.…”

“…As a reference, we compare the accuracy with the predicted GP (PGP) introduced in [20] and the IC-κESM introduced in [19]. The PGP is obtained by neglecting the uncertainty on H given the actual CSI, and is calculated by substituting H by μ H|CSI in the expression (15) and using this deterministic value of Y to replace the random variable Z in (17).…”

“…The performance of the SU network is shown In Fig. 3, we show the difference in performance between optimizing the AEGP, the PGP (as in [20]), and the IC-κESM (as in [19]). We show the performance for f d τ d equal to 0.05 and 0.2.…”

“…2. Unlike the ad hoc approaches used in our previous work [19,20], we now start from the optimal expression for the EGP. By using the statistical approximation for the effective SNR, which we introduced in [21], we now derive an analytical, tractable approximation for the EGP, which we call the approximate EGP (AEGP).…”