5.2.5 Structure of the mixed-use block: Blocks B and C

The spectrum proposed to be released on a geographic basis has several potential uses but the availability of equipment will be a significant factor. If two-way services are to be implemented, these may require two spectrum sub-bands, one for each direction of transmission. In general terms, for frequency division duplex services (FDD) the narrower the frequency separation the greater the level of cost, and eventually impracticability, occurs. It is normal practice to allow for a reasonable frequency separation, for example cellular technology at 800 and 900 MHz uses a 45 MHz separation. However use of a similar separation within a contiguous 100 MHz band may limit the amount of useful spectrum that can be used. Use of two separate sub-bands would be more efficient if FDD type services are to be used. However it is acknowledged that technologies such as time division duplex (TDD) can avoid the need for two sub-bands but at the expense of greater radio frequency coordination and potential time synchronisation and common up-link-down link ratios for different services. While the types of technology are not yet known there appears to be some advantages, and few disadvantages, in planning for two sub-bands for potential FDD type usage.

Question 10

Do you agree with the placement of the spectrum released in geographic areas in two portions, i.e. from approximately 500 to 550 MHz and from approximately 650 to 700 MHz? If not, what would you prefer and why?