Wi-Fi and LTE-LAA coexistence problems, challenges and features in 5GHz unlicensed bandwidth

Abstract

The demand for high data rate and stable Quality of Service (QoS) from cellular networks’ subscribers is a huge challenge for cellular operators. To overcome this issue (providing high data rate and stable QoS) it requires more bandwidth. The lack of licensed bandwidth and also its high cost make it hard for operators to overcome this issue. To find a fair solution and expand the capacity of cellular networks, operators started deployment of Long Term Evolution (LTE) in unlicensed bandwidth, exactly utilizing 5GHz unlicensed bandwidth in small cell scenarios. The extension of LTE to the 5GHz unlicensed bandwidth where it is already in used by Wi-Fi will create huge coexistence problems between Wi-Fi and LTE. It results from that Wi-Fi and LTE have different channel access mechanisms. This paper presents the channel access mechanisms of Wi-Fi and LTE-Licensed Assisted Access (LTE-LAA), coexistence problems, challenges, privileges, coexistence features of LTE and Wi-Fi and Finally, we conducted the simulation for LAA based on Listen Before Talk (LBT) mechanism and Wi-Fi to find that how LAA with LBT mechanism is friendly to the Wi-Fi networks when they share the same bandwidth. The simulation results illustrate that LAA based on LBT channel access mechanism by alone cannot bring a fair coexistence between these two technologies, it needs further improvement.