Transmission Experiment of Bandwidth Compressed Carrier Aggregation in a Realistic Fading Channel

In this paper, an experimental testbed is designed to evaluate the performance of a bandwidth compressed multicarrier technique, termed spectrally efficient frequency division multiplexing (SEFDM) in a carrier aggregation (CA) scenario. Unlike orthogonal frequency division multiplexing (OFDM), SEFDM is a nonorthogonal waveform which, relative to OFDM, packs more subcarriers in a given bandwidth, thereby improving spectral efficiency. CA is a long-term evolution-advanced (LTE-Advanced) featured technique that offers a higher throughput by aggregating multiple legacy radio bands. Considering the scarcity of the radio spectrum, SEFDM signals can be utilized to enhance CA performance. The combination of the two techniques results in a larger number of aggregated component carriers (CCs) and, therefore, increased data rate in a given bandwidth with no additional spectral allocation. It is experimentally shown that CA-SEFDM can aggregate up to seven CCs in a limited bandwidth, while CA-OFDM can only put five CCs in the same bandwidth. In this paper, LTE-like framed CA-SEFDM signals are generated and delivered through a realistic LTE channel. A complete experimental setup is described, together with error performance and effective spectral efficiency comparisons. Experimental results show that the measured bit error rate performance for CA-SEFDM is very close to CA-OFDM and that the effective spectral efficiency of CA-SEFDM can be substantially higher than that of CA-OFDM.