ch aggregate LTE carriers in a licensed spectrum with LTE or WiFi carrier in an unli- censed spectrum, respectively. MulteFire adds more capacity in crowded areas, as well as providing enhanced local broadband access even without a SIM card (similar to WiFi) and open possibilities for IoT verticals for LTE value added services. Regarding the use of LTE and WiFi in unlicensed bands (at 5 GHz), they will both con- tinue to be utilized. However, there are differences regarding the utilization of spectrum LTE-U/LAA (Licensed Licensed assisted access) spectrum LWA (LTE WiFi aggregation) Multefire Unlicensed spectrum WiFi (IEEE 802.11ac/ad) Figure 5.10 LTE-WiFi aggregation scenarios. 5.5 WiFi VS. LTE/LTE-Advanced in Unlicensed Bands: The QoS Viewpoint as well as QoS possibilities. For example, WiFi cannot guarantee strict QoS due to the DCF mechanism for access to the wireless channel (it can provide certain traffic differ- entiation by using the EDCA, as discussed in the previous section). Therefore, in the case of LWA, Internet traffic should be carried over the WiFi carrier while real-time traffic is preferably carried over the LTE carrier due to available strict QoS support based on bearers and associated QCIs. What is the QoS effect of transmitting mobile LTE signals over an unlicensed band? It provides better QoS and higher efficiency in radio resource utilization than WiFi in the same spectrum. There are two types of interworking between LTE and WiFi for serving the same users: offloading mobile data traffic to WiFi, which is a traditional approach used in previous mobile generations (e.g. GPRS, UMTS); offloading WiFi traffic to LTE (opposite to traditional offloading between mobile net- works and WiFi), which is targeted at provision of better QoS to the users transferred from WiFi to LTE in the unlicensed band in a local area (e.g. home, office, public place). However, there are several challenges regarding the use of unlicensed spectrum between multiple technologies such as LTE and WiFi. One challenge is to h