US 5,970,412 AGranted

Overload control in a packet-switching cellular environment

OwnerNicholas Frank Maxemchukinventor

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Abstract

An improved cellular arrangement is created with mobile units that are responsive to control signals that direct the mobile units to modify the rate of packet transmissions in case of channel overload. A mobile unit in such an arrangement encodes either the speech signal, or only a portion thereof that is sufficient to reproduce a lower fidelity speech which is still intelligible--and at a lower rate. In another embodiment, the mobile unit creates a second stream of packets, also at a lower rate. The second stream complements the first stream of packets in its lower rate form, to allow reproducing the speech signal with high fidelity. Operationally, such a mobile unit is responsive to a base station which, under overload conditions, directs the mobile unit to transmit packets at the lower rate (and the lower fidelity). Optionally, the base station can also directs the mobile unit to send the second stream of packets over a different channel.

Claims9

Dependent claims

A cellular arrangement having mobile units and cells, where each cell covers a roughly circular geographical area by means of a base station at the center of the cell, and where a plurality of cells are arranged to cover a larger geographical area in roughly honeycomb pattern of hexogons that are centered a distance of nominally D distance units from each other, characterized in that:

the base stations include transmitters that are provisioned to transmit over one of three mutually exclusive channels, where the channel selected for one base station is different from the channels of all adjacent base stations, and is the same channel as the channel of base stations that are removed from said base station by a distance that is nominally 3D.sqroot.3/2 distance units, and where the base station transmitters are further provisioned to transmit with enough power to allow mobile units to receive base station transmissions at a distance that is nominally (1-k)D.sqroot.3 distance units, where k is a number greater than 0 and less than 1/3, and
the mobile units are provisioned to transmit with enough power to allow a base station that is nominally 3D.sqroot.3/2 distance units away to receive the signal transmitted by a mobile unit, each mobile unit being further provisioned with a circuit for informing the mobile unit whether the base station is receiving more than one packet at any time.

Dependencies are inferred from the claim text.