A Context-Aware Cognitive SIMO DL Transceiver for LTE HetNet Power Efficiency and Throughput Enhancement

In this paper, we propose a new single-input multiple-output (SIMO) context-aware cognitive transceiver (CTR) that is able to switch to the best performing modem in terms of link-level throughput and allows to decrease macro transmission power without loosing performances. On the top of conventional adaptive modulation and coding (AMC), we allow the context-aware CTR to make best selection among three different pilot-utilization modes: conventional data-aided (DA) or pilot-assisted, non-DA (NDA) or blind, and NDA with pilot which is a newly proposed hybrid version between the DA and NDA modes. We also enable the CTR to make best selection between two different channel identification schemes: conventional least-squares (LS) and newly developed maximum-likelihood (ML) estimators. Depending on whether pilot symbols can be properly exploited or not at the receiver, we further enable the CTR to make best selection among two data detection modes: coherent or differential. It will be seen that using our new cognitive transceiver allows to 1) decrease acro transmission power to the half (typically from 40 to 20 Watts), and 2) achieve an average throughput gain as high as 140% and a 5^th percentile throughput gain reaching 230% for pico-cells in case of low UE´s clustering distributions.