Investigation on Optimum Radio Parameter Design in Layered OFDMA for LTE-Advanced

This paper investigates the optimum radio parameters, i.e., numerology, in layered orthogonal frequency division multiple access (OFDMA) for long-term evolution (LTE)- Advanced. Similar to the layered OFDMA concept, it was agreed at the 3GPP RAN WG1 meeting that the entire transmission bandwidth in LTE-advanced should comprise multiple frequency blocks called component carriers to achieve a wider system bandwidth than that for the current LTE (Rel-8 LTE). We investigate the optimum radio parameters in the frequency domain including the need for an inter-component carrier guard band (GB). In the simulation evaluations, we set the parameters for the receiver filter assuming the worst case that satisfies the minimum requirement specified in Rel-8 LTE. Simulation results show that the loss in the average received signal energy per symbol-to-noise power spectrum density ratio (Es/No) satisfying the required block error rate compared to the case without an inter-component carrier GB is negligible irrespective of the modulation scheme and coding rate. As a result, we conclude that the inter-component carrier GB is unnecessary and can be minimized to 19 subcarriers in the downlink while retaining the same number of subcarriers within a component carrier as that for Rel-8 LTE.