On the Performance of FDD and TDD Systems in Different Data Traffics: Finite Block-Length Analysis

We consider a bi-directional point-to-point links and study the data transmission efficiency of frequency division duplex (FDD) and TDD (T: time) schemes with a bursty communication model. We use the recent results on the achievable rates of finite-length codes to analyze the end-to-end throughput and the data payload for TDD and FDD in the cases with codewords of finite length including the impact of guard time for TDD and guard bands for FDD. Also, in case of TDD we study the impact of adaptive resource allocation on the link throughput. As we demonstrate, TDD-based adaptive resource allocation based on the data traffic improves the performance over non-adaptive TDD and FDD schemes significantly. For instance, consider the data rates 0.1 and 1 bit/symbol and data request probabilities 0.2 and 0.6 in the two different directions, respectively, and Rayleigh fading conditions. Then, for a broad range of codewords lengths and moderate/high signal-to-noise ratios, the implementation of adaptive TDD improves the link throughput, compared to the nonadaptive duplexing by more than 50%.