Random Access or Scheduling: Optimum LTE Licensed-Assisted Access to Unlicensed Spectrum

To deploy long-term evolution advanced (LTE-A) networks on unlicensed bands, licensed-assisted access (LAA) has been regarded as an unprecedented technology in the third generation partnership project (3GPP) Rel-13. However, due to uncontrollable interference from collocated WiFi networks, a particular LAA-WiFi hidden terminal problem may occur, thus degrading the performance of the existing scheduling-based radio access in LTE-A. To provide foundations for LAA standardization, we analytically derive the optimum radio access for LAA, which reveals a dynamic switch between scheduling-based and random access schemes. The switching condition derived in this letter thus suggests the optimum design for LAA networks.