Opportunistic spectrum access in TVWS: A comparative coexistence study for LTE

Abstract

In this paper, we study the coexistence issues of LTE systems operating in the TV white spaces. The study includes a proposal for an appropriate system design as well as a discussion on the LTE system's self-configurability to avoid potential interference to other systems when the resource allocation is made flexible. This is evaluated in terms of achievable PHY-layer throughput and block error rates (BLER) in coexistence scenarios with digital terrestrial TV (DTT) and wireless microphones (WM). Furthermore, the study makes exclusive comparisons between the current LTE PHY interface of cyclic-prefix OFDM (CP-OFDM) and one of its alternatives, the offset-QAM OFDM (OQAM-OFDM) scheme. Therefore, the aspects of interference robustness, system flexibility and complexity issues are considered. The main outcome of this study is that an LTE system based on OQAM-OFDM offers higher data rates and conforms better to potential regulatory rules than the current CP-OFDM implementation. The OQAM-OFDM scheme is significantly more robust and delivers higher data rates, in particular for the coexistence with narrow-band services. Finally, through the complexity analysis, we conclude that such performance-complexity trade-off may be reasonable in the future as the overall system complexity of OQAM-ODFM is only incremental.