Delay constrained throughput optimised joint scheduling and link adaptation scheme based on imperfect channel state information

This study presents novel joint scheduling and link adaptation schemes (JSL) to maximise a weighted sum of throughputs of wireless links, while their possibly different minimum required throughputs and packet error rate (PER), average power and delay constraints are provisioned. Weights are assigned based on the importance and requirements of the links. Notable features of the proposed scheme in comparison with the previously presented utility based scheduling schemes are: (a) in the designed scheme a statistical bound is presented for the delay instead of average delay constraint or long term queuing delay behaviour, (b) designed transmission scheme utilises adaptive modulation and coding provisioning PER constraint and may be integrated with H automatic repeat request in data link layer to provide error free communication, (c) the presented schemes are designed based on imperfect signal-to-noise ratio (SNR) estimate of the links. In addition to an analytical approach, a JSL scheme based on sub-gradient projection (JSL-SP) is presented in which there is no need to have SNRs probability density functions. Numerical results demonstrate how the proposed JSL schemes outperforms the benchmark schemes and effectively meets various user´s requirements.