Flexible spectrum usage for the future broadband mobile and fixed convergence

To meet the tremendous increase of user demands on the global market, it is necessary to find more available spectrum resources for the future broadband mobile and fixed convergence. However, not only would spectrum be limited and become more and more precious in the future, but the spectrum regulation-making process still have a long way to go. Therefore, the insufficiency of spectrum resources will remain and will not be completed changed in a short time. In this paper, we try to avoid the air interface becoming the bottleneck for the future broadband mobile and fixed convergence from the solutions of flexible spectrum usage and the sharing of spectrums of different radio services. For this purpose, we provide two solutions of flexible spectrum usage for the mobile broadband applications, from the operational and regulatory perspective. The first solution is to enable the deployment of advanced technologies such as multi-band, multi-carrier aggregation to enhance the spectrum efficiency and broadband experience. Heterogeneous networks can also significantly improve the capacity and materialize the networks convergence via the mobile platform. The second solution is the practical implementation of the possible candidate bands identified for IMT. In addition to the traditional methods adopted such as carrier aggregation, multi-band combination etc, the low power pico cell, indoor coverage, and CRS through spectrum sharing and dynamic allocation has been addressed. Finally we compare the two mainstream duplexing schemes used in flexible spectrum usage, Frequency Division Duplex (FDD) and Time Division Duplex (TDD). In light of the advantages of TDD in the flexible spectrum usage, as the paper summarized, we believe TDD is the convincible solution in the future broadband mobile and fixed convergence.