Multiplex communications – Wide area network – Packet switching
Patent
1992-04-21
1994-03-15
Olms, Douglas W.
Multiplex communications
Wide area network
Packet switching
370 691, 370 76, 370118, 375 60, 455 62, 455 63, 455 673, 455115, 455125, H04J 112, H04J 116, H04Q 1102
Patent
active
052951383
ABSTRACT:
A method and apparatus for operating a frequency division multiplexing (FDM) transmitter within a common communication channel is disclosed. The carrier frequency for each separate channel is adjusted for minimizing intermodulation interference. The system randomly allocates each separate channel within the available bandwidth to provide an initial set of separate channel allocation and corresponding carrier frequencies. Thereafter carrier to intermodulation ratio (C/IM) on each channel is measured and the worst channel with the lowest carrier to intermodulation ratio (C/IM) is removed. The system then repeatedly inserts a channel in available unoccupied bandwidth to produce the largest minimum carrier to intermodulation ratio (C/IM). The deletion and insertion continues until no improvement in minimum carrier to intermodulation ratio (C/IM) can be achieved for said random allocation of separate channels. The selected set of separate channel allocations is further fine-tuned by deleting the worst channel with minimum carrier to intermodulation ratio (C/IM) and deleting one other channel from said separate channel allocations to provide a particular dual channel deletion. The system then repeatedly inserts two channels in available unoccupied bandwidth which produces the largest minimum carrier to intermodulation ratio (C/IM). The system continues on dual deletion and insertion until no improvement in minimum carrier to intermodulation ratio (C/IM) can be achieved for said random allocation of separate channels. The carrier frequencies are then tuned according to said set of separate channel allocation.
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Greenberg A. Frederick
Gu Goson
Hatcher G. Stephen
Hsu Alpus H.
Northwest Starscon Limited Partnership
Olms Douglas W.
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