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MMDS takes advantage of a microwave
transmission technology known as wireless cable, which is a
microwave technology used to deliver analog cable television service
over the air to rural areas that cannot be served economically by
wired cable.
The areas served by wireless cable
were too sparsely populated to generate strong revenue as reflected
in the lack of financial success for wireless cable operators. But
the success of DBS and continued progress with digital technology (such as
MPEG, digital modulation techniques, and advances in semiconductors)
changed the perception of microwave from simply a rural delivery
system to a system that could be used in urban areas. Telephone
companies view microwave as a fast-start service to allow video
distribution that can compete against cable and DBS.
In 1996, the FCC conducted spectrum
auctions for MMDS. The FCC auctions offered 200 MHz in each of the
nation's 493 basic trading areas (BTAs). A BTA represents a
contiguous geographic market. BTA boundaries are drawn on county
lines. The counties are aggregated by considering physical
topography, population, newspaper circulation, economic activities,
and transportation facilities (such as regional airports, rail hubs,
and highways). The BTA concept was licensed by the FCC from Rand
McNally.
MMDS frequencies fall in the range of
2.5t of a transmitter is 30 to early wireless cable operators, the
operator can derive an aggregate of approximately a gigabit (Gb) of
bandwidth, which is sufficient bandwidth to offer 150. This is channel capacity
to DBS. Note that the bit rate available to the MMDS operator is
comparable to the bit rate available from DBS systems, even though a
narrower spectrum is available. This is because MMDS uses more
aggressive modulation techniques. DBS has 500 MHz of bandwidth using
QPSK modulation (2 b/Hz). MMDS has 200 MHz using QAM-64 modulation
(6 b/Hz). After overhead bits and error correction, both DBS and
MMDS can achieve nearly 1 Gb of bandwidth. The auction rules
provided no regulations regarding spectrum use. Operators are free
to decide whether to offer Internet access, TV, or a combination of
the two.
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