LTE LAA Coexistence with Wi-Fi: Performance Evaluation for Priority Classes

Recently, the development of the Licensed-Assisted Access (LAA) standard has allowed Long-term Evolution (LTE) devices to not operate exclusively in licensed bands but also in unlicensed ones. However, the operation in unlicensed bands is shared with other radio systems and LAA systems can coexist with Wi-Fi devices implementing the IEEE 802.11 standard. This paper characterizes the performance of such a coexisting scenario, by considering that a secondary LAA system coexists with a primary IEEE 802.11 system. The main contribution of this paper is the assumption of the recent improvements introduced in LAA, such as multiple access classes, timings, and upload/download operation, which are now part of Release 16. The performance of the two coexisting systems is compared for different access priority classes at the medium access control sublayer level. We developed a random access simulator, which is validated with theoretical models already proposed in the literature for the IEEE 802.11 standard. The simulator is then parameterized according to the LAA and IEEE 802.11 parameters to run coexisting scenarios. The simulated coexisting scenarios include multiple access priority classes and quantity of IEEE 802.11 and LAA competing nodes in uplink and downlink directions. The simulation results show that the LAA nodes benefit more from the coexisting environment, which increases their throughput. Comparatively to IEEE 802.11, the devices adopting the LAA achieve higher performance for voice and best-effort traffic classes, although a balanced performance is found for video traffic classes.