Network Mapping Is Always Provisional

Cell mapping is highly specific in terms of frequency band selected; modulation technique; the
sensitivity of the radio; the types of services supported, such as best-effort high speed, access,
voice telephony, rich multimedia, full mobility, and so on; and the distribution of subscriber
sites. Should the network operator decide to transmit at another frequency than that used initially
or attempt to offer services requiring constant throughput rates, the specific network
architecture in use previously may not be adequate. It follows then that if the network at first
offers only basic access but the intention is to move toward diversified services, then the network
should be overdesigned in terms of basic access. A network that can support advanced
multimedia well can nearly always provide basic access, but the converse is not true.
The Importance of Projecting Growth Patterns
A third consideration is closely related to the second. One should always keep in mind that
bandwidth can be throttled down from a set maximum but never throttled up, at least not
without major equipment upgrades. It follows that each cell should be designed to deliver
however much capacity is likely to be demanded by the customers over the lifetime of the network. If, for instance, a large business park full of 20 likely high-usage customers is situated
two miles from the nearest base station in a 5.8GHz network, one may want to consider building
a base station nearer to those businesses or at least securing location rights that will enable
one to do so in the future. One may be able to serve the single subscriber that one currently has
in that business park perfectly adequately from two miles away, but one may not be able to
serve five or ten. In other words, the mapping of the network must extend into the future and
must anticipate the eventual maturity of the network with the full complement of base stations
that will eventually have to be in place. Such projections will never be entirely accurate
because subscriber take rates, equipment advances, and changes in urban topography are
never completely predictable. One can make informed guesses as to growth and change in the
network, however, and then model a distribution of base stations based on sound engineering
principles.
A final general design principle is to provide oneself with choices in terms of base station
placement. In planning for the future one can never be absolutely certain that a desired site
will be available when one is ready to occupy it. A building where the owner has agreed to provide
roof rights may be sold. An antenna tower that has space today may be filled tomorrow.
If one does not have options at the time when expansion is indicated, the network may not be
able to reach potential customers.