WiMax Operator's Manual

CHAPTER 3 ■ STRATEGIC PLANNING OF SPECTRUM AND SERVICES 53
latency and jitter and minimum transit times. Ordinary best-effort service through the public
Internet will not do. Chapter 6 covers this topic in more detail.
Mobile Voice
Finally you must consider the issue of broadband operators moving into the mobile telecommunications
space and competing with cellular and Personal Communications Service (PCS)
operators. Several hardware manufacturers, including IP Wireless, Flarion, MeshNetworks,
and Navini, already support mobility, and each has suggested that mobile voice services are
well within the scope of a broadband wireless operator.
Such services could enhance the attractiveness of the broadband wireless network to
some customers especially if a single terminal, presumably some sort of smart phone, could be
made to serve as both a phone and a high-speed access device—which is really the whole
notion behind third-generation cellular. But before this kind of far-reaching convergence can
take place and win the acceptance of network operators, several developments will have to
happen.
First, the 802.20 mobile broadband standard will have to be completed (or, alternately, the
less comprehensive 802.16e amendment to the 802.16 standard will have to be completed). To
what extent this will be complementary to 802.16a remains to be determined, but it will most
likely apply to the same bands currently covered by 802.16. Second, the handset manufacturers
will have to produce phones that conform to the new standard, because without phones,
mobile telephony over broadband will remain conjectural. Third, some sort of modus vivendi
will have to be fashioned by the broadband wireless service providers and the mobile telecom
incumbents that themselves are moving toward fourth-generation systems, which will likely
have much in common with the 802.20 networks. Already mobile phone operators are
discussing using unlicensed frequencies in the 2.4GHz band to augment the mobile bands
during large downloads and are anticipating further allocations of licensed bandwidth to
support true high-speed services.
I do not expect 802.20 to be finalized until 2006 at the earliest, and there is no telling when
802.16e will emerge. A further span of time will be required for chipmakers to embody the standards
in silicon, and yet more time must elapse before any kind 802.20- or 802.16e-compliant
terminals become available. Gaining the support of handset manufacturers becomes essentially
a chicken-and-egg conundrum since the manufacturers are not interested in undertaking
a small production run. Still, Nextel (now part of Sprint), with its proprietary Integrated
Digital Enhanced Network (IDEN) system, managed to obtain handsets for its few million
subscribers, so 802.20- or 802.16e-enabled phones are not inconceivable within two or three
years, though prices are unlikely to be comparable to those of cellular units.
In the meantime, the cellular industry will proceed slowly but inexorably with the development
of fourth-generation systems. Fourth-generation will share in common with 802.20
the use of packet transmissions to convey voice messages and an elimination of circuits altogether
except to serve legacy customers. It will also provide much higher throughputs for data,
purportedly in the megabits per second, at least in burst mode.
The question then becomes, how will the two services differentiate themselves in the
marketplace, or will they? Similar questions were asked concerning PCS when it emerged in the
early 1990s, the supposition at the time being that PCS would fill a different market niche. It did
not, and ultimately fourth-generation cellular and broadband wireless may not fill different
niches either.