1. Introduction
The ITU Table of Frequency Allocations allocates different parts of the radio frequency spectrum to radiocommunication services. Often services allocated to the same frequency band can cause mutual interference unless certain sharing constraints are observed. Therefore, the ITU Table of Frequency Allocations can be regarded as a menu from which each administration constructs its National Table of Frequency Allocations by selecting the services that it wants to favor on its territory. Proponents of BWA will often say that ITU has “approved” its use in the C-band because there is an allocation for it. This is misleading since it is the administration that decides in its National Table of Frequency Allocations which services to favor.
Some administrations do not have a National Table of Frequency Allocations and simply rely on the ITU Table. However, this can lead to difficulties. For example, in Region 3 (Asia), in the band 3.5 – 4.2 GHz the services FSS, FIXED and MOBILE are all co-primary (see Annex 2). Based on these allocations some administrations have licensed both FSS and BWA in the C-band. Even with frequency separation between the services, FSS is still subject to interference.
Annex 1 gives links to National Tables of Frequency Allocations (where they exist.)
2. Broadband Wireless Access (BWA) Allocations
WiMAX is the best known example of a BWA technology. WiMAX is comprised of a family of IEEE Standards that include standards for both a fixed service and a mobile service. For example, the 802.16d 2004 standard is for a fixed service (non line-of-sight) while the 802.16e 2005 standard is for a mobile service. Fixed WiMAX networks can be deployed under the FIXED service in the ITU Table of Frequency Allocations and mobile WiMAX under the MOBILE allocation.
Traditionally, the main FIXED service sharing the FSS bands was radio-relay networks, which were point-to-point, making co-existence relatively easy with well-developed coordination procedures. However, the BWA service now being deployed under the FIXED service is point-to-multi-point and does not share well with the FSS. Due to the convergence of fixed and mobile applications there are proposals under WRC-11 agenda item 1.2 to merge the FIXED and MOBILE service categories into one category. (Satellite operators should follow this issue carefully due to the potential impact on FSS.)
Mobile WiMAX has been recognized as an International Mobile Telecommunications (IMT) technology. WRC-07 adopted opt-in footnotes in the bands 3.4 – 3.5 GHz and 3.5 – 3.6 GHz designating these bands for IMT for administrations that wanted their names included in these footnotes. The footnotes designating bands for IMT are for mobile allocations on a primary basis and all contain words to the effect that “This identification does not preclude the use of this band by any application of the services to which it is allocated and does not establish priority in the Radio Regulations.” In spite of this wording, administrations asking to be included in such a footnote are likely to show a preference for IMT technologies when issuing licenses.
Annex 2 gives the ITU Table of Frequency Allocations for the C-band.