1. Background: Mobile technology evolution
- Mobile technologies are undergoing a rapid change. Because it is impossible to predict what mobile technologies will look like in 2031, operators have to base their decisions on the current standards under development by the ITU and other industry standards bodies.
- Since the advent of IMT-2000, significant enhancements to the air interface are now standardised and deployed at least once per year.
- Rec M 1457 that specified the radio interface for 3G in the year 2000 is now undergoing its sixth revision.
- IMT Standards:
There are two dominant IMT standards; one based on the CDMA standard has a carrier bandwidth of 1.25 MHz, the other based on the UMTS standard has a carrier bandwidth of 5 MHz.
Both standards are aiming to provide long term evolution (LTE) symmetrical peak data rates of 100 Mbps (see pages 7 and 8). To provide such high data rate operators need wider carrier bandwidths than in current 3G systems. The 3GPP and 3GPP2 are both considering a value of 20 MHz. This corresponds to a peak spectrum efficiency of 5 b/s/Hz.
It should be noted that even with 20 MHz wide carriers, the peak data rates will only be available at a vanishingly small part of the cell area.
In addition the standard aims to enable the realisation of peak data rates over a much larger cell area; the target is 50%. The increased area spectrum efficiency will in turn require reduced cell sizes and complex antenna arrangements.
- IMT Advanced Standards:
- Beyond the IMT family of technologies, the ITU is currently planning the standardisation of IMT Advanced.
- The goal of IMT Advanced is to provide 100 Mbps for mobile services and 1 Gbps for nomadic applications.
- The 100 Mbps for mobile services is to be available over 80% of the cell area.
- See Appendices E and F.
The IMT Advanced systems are likely to come into deployment post 2015, though Japan and Korea may do an earlier deployment.
- ITU-R WP 8F has recently completed its estimates of spectrum for IMT Advanced, that will be considered by WRC-07 under agenda item 1.4.
- Radio characteristics of IMT Advanced are not yet standardised. However for the purposes of spectrum estimates, carrier bandwidths of 20 MHz and 120 MHz have respectively been assumed for the mobile and nomadic components of IMT Advanced.
- WRC-07 will consider the identification/allocation of spectrum for IMT Advanced. One possible approach is to identify new bands for exclusively IMT Advanced. Another approach is to ‘re-farm’ existing spectrum for the IMT family of technologies (including IMT Advanced) and also identify any new spectrum. This approach does not give a special regulatory status to a band for a particular application and instead enables administrations to deploy IMT Advanced over an band where it is permitted.
- One of the leading candidate bands for IMT Advanced is the 3.4-4.2 GHz band. This band is already in private hands in NZ and is also not channelled appropriately for the requirements of IMT Advanced. Therefore, the re-farming approach may be preferable for NZ. It will permit the use of 850 and 900 MHz bands for IMT Advanced technologies.
In summary: Our belief is that 20 MHz wide carriers will be the unit of future wireless systems. As the renewal period of the cellular rights includes the time period of LTE and IMT Advanced, Telecom intends to use all of the 850 MHz spectrum for the ongoing enhancement of its mobile network.