phát sóng phương tiện truyền thông trên tiền đề rằng quang phổ là một nguồn tài nguyên độc đáo và hiếm. Trên thực tế, hầu hết các giả định rằng nền tảng cho mô hình quang phổ hiện tại xuất phát từ phát thanh truyền thống | Conclusion Is the Future of Voice Communications 237 broadcast media on the premise that spectrum is a unique and scarce resource. Indeed most assumptions that underlie the current spectrum model derive from traditional radio broadcasting and are oblivious to wireless broadband Internet applications. The FCC has recently conducted a series of tests to assess actual spectrum congestion in certain locales. These tests which were conducted by the FCC s Enforcement Bureau in cooperation with the task force measured use of the spectrum at five major . cities. The results showed that while some bands were heavily used others either were not used or were used only part of the time. It appeared that these holes in bandwidth or time could be used to provide significant increases in communication capacity without impacting current users through use of new technologies. These results call into question the traditional assumptions about congestion. Indeed it appears that most of spectrum is not in use most of the time. Today s digital migration means that more and more data can be transmitted in less and less bandwidth. Not only is less bandwidth used but innovative technologies like software-defined radio and adaptive transmitters can bring additional spectrum into the pool of spectrum available for use. Spectrum Scarcity The Solution In analyzing the current use of spectrum the task force took a unique approach looking for the first time at the entire spectrum not just one band at a time. This review prompted a major insight There is a substantial amount of white space out there that is not being used by anybody. The ramifications of the insight are significant. It suggests that while spectrum scarcity is a problem in some bands some of the time the larger problem is spectrum access how to get to and use those many areas of the spectrum that are either underutilized or not used at all. One way the FCC can take advantage of this white space is by facilitating .
