Coexistence of LTE-U and Wi-Fi sharing unlicensed spectrum in ultra-dense networks

Spectrum sharing is an important approach to meet the requirements of the exponential increase in the demand for capacity in wireless communication. Long-Term Evolution (LTE) and Wi-Fi are two of the most remarkable wireless technologies at present. LTE-Unlicensed (LTE-U) bands have been introduced by the 3rd Generation Partnership Project (3GPP) to increase throughput and offload data from crowded licensed bands. Researches indicate that LTE-U exerts significant interference on Wi-Fi in dense and ultra-dense scenarios, preventing the harmonious coexistence of LTE-U and Wi-Fi. Therefore, it is necessary to adopt the coexistence scheme for restraining interference between LTE-U and Wi-Fi in unlicensed bands. In this paper, a dynamic on/off scheme is proposed to address the coexistence issues of LTEU and Wi-Fi when sharing unlicensed spectrum. We choose GNU Radio and Universal Software Radio Peripheral (USRP) in this study to construct a real-time test platform for investigating the performance of coexistence schemes based on software-defined radio (SDR). Using this platform, we conducted real-time experiments on the coexistence schemes of LTE-U and Wi-Fi in real wireless environments. The test results showed that the dynamic on/off scheme has better performance than the static on/off scheme in dense and ultra-dense scenarios. Harmonious coexistence can be achieved by adopting the dynamic on/off scheme in dense and ultra-dense scenarios.