What will be the future of LTE-U?


There is a general agreement that with demand for data at an all-time high there is a need to find solutions for higher mobile data speeds. One of the means to achieve this is more spectrum, however the licensed spectrum has limited availability and is an expensive proposition for the service providers. That’s why there is so much interest in exploring the use of unlicensed spectrum of 5Ghz for LTE which is currently used majorly by Wi-Fi along with other technologies. The LTE in unlicensed high frequency band of 5Ghz is suitable for short range dense and indoor deployments. With enterprise deployments of LTE small cells picking up, this is all the more reason for so much attention on unlicensed bands for LTE now.

Since there are existing huge deployments of wireless technologies such as Wi-Fi in unlicensed 5Ghz band, the fairness of operation for all the technologies is very important. LTE, in its original form was defined with the assumption of dedicated frequency band available for it. It was therefore not designed to co-exist with other technologies and can starve other technologies of opportunity to receive and transmit data.

LAA and LWA have emerged as the two most viable options for LTE in unlicensed bands. LAA has introduced changes in LTE radio technology by defining ‘Listen before Talk’ mechanism so that it provides fair opportunity to other radio technologies to co-exist. LWA, on the other hand utilizes the already proven Wi-Fi technology in the unlicensed band along with LTE in licensed band and aggregates the data from the two technologies.

Both the technologies are viable and are equally suitable for LTE in unlicensed band deployments, the choice will be mainly driven by the deployment scenarios and the business case for the operators. LAA is more suitable for green field deployments where carrier Wi-Fi is not deployed, whereas LWA could be suitable for operators with already deployed carrier Wi-Fi so that they can leverage the already deployed infrastructure. Some operators are leaning towards LAA since the use of unlicensed band or Wi-Fi is not visible to the consumers in this case. In the case of LWA, consumers might perceive that they are being charged for Wi-Fi access which was free till now.

The availability of customer devices and handsets and the development of the whole ecosystem will also determine which technology is finally widely adopted and deployed. This would require changes in the operators’ back end system for billing and charging as well. The various options for LTE in unlicensed band was one of the major discussion theme in Small Cell World Summit in 2016 indicating considerable interest in the technology, however with the changes required in the infrastructure and the availability of devices it is expected to see general deployments not before late 2017 or later.

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