Femtocells: Opportunities and Challenges for Business and Technology

Appendix

A Brief Guide to Units and Spectrum

A variety of units are used in this book, particularly as regards quantities and speeds of data. There are also references to various spectrum bands. This appendix is intended to assist those unfamiliar with these terms.

The SI system of units is adopted for small-cell terminology and for describing large quantities of data. The original SI prefixes are listed in Table A.1. To complicate matters, when describing quantities of binary data, the prefix may indicate a multiple of either 1000 or 1024 bytes, so we have the outcomes listed in Table A.2. There is some tendency to use 1000 for data rates (so 1 kbps = 1000 bits per second) and 1024 for data quantities (so 1 kB = 1024 bytes) but there is no consistent rule.

There is less ambiguity in the description of frequencies, where 1 MHz = 1,000,000 hertz and 1 GHz = 1,000 MHz. Frequencies are described in general terms as VHF (30–300 MHz), UHF (0.3–3.0 GHz) or SHF (3–30 GHz). Regarding specific frequency bands, femtocells can be deployed in any of the frequency bands supported by the relevant mobile standard, although initial deployments favour the use of the higher frequency bands such as the 1.9 GHz or 2.1 GHz bands. The main mobile frequency bands in current use around the world are shown in Table A.3.

Table A.1 Prefixes used in SI units

Table A.2 Data quantities

Table A.3 International ...