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A METHOD TO INCREASE RADIO CHANNEL UTILIZATION IN REMOTE DATA COLLECTION APPLICATIONS

IP.com Disclosure Number: IPCOM000006501D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2002-Jan-09
Document File: 4 page(s) / 218K

Publishing Venue

Motorola

Related People

Kenneth Rideout: AUTHOR

Abstract

In radio data systems where the preponderance of data message traffic is directed inbound (from remote to central), the outbound channel (i.e., the allocated RF frequency) is often under utilized. This condition would be compounded as additional bi-directional channels were needed to satisfy a given inbound data throughput require- ment. At some point, the totality ofthe unxwdbandwidth of the outbound channels would equal or exceed the usable bandwidth of one or more channels. This would be the case with conventional channel organization and contention protocols, where bi-directional channels are incrementally added until the peak throughput require- ments are met. At the same time, the unused bandwidth of the outbound channels increases, but remains inac- cessible for satisfying additional inbound demand.

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MOlOROLA INC. Technical Developments Volume 16 August 1992

A METHOD TO INCREASE RADIO CHANNEL UTILIZATION IN REMOTE DATA COLLECTION APPLICATIONS

by Kenneth Rideout

  In radio data systems where the preponderance of data message traffic is directed inbound (from remote to central), the outbound channel (i.e., the allocated RF frequency) is often under utilized. This condition would be compounded as additional bi-directional channels were needed to satisfy a given inbound data throughput require- ment. At some point, the totality ofthe unxwdbandwidth of the outbound channels would equal or exceed the

usable bandwidth of one or more channels. This would be the case with conventional channel organization and contention protocols, where bi-directional channels are incrementally added until the peak throughput require- ments are met. At the same time, the unused bandwidth of the outbound channels increases, but remains inac- cessible for satisfying additional inbound demand.

  Customers are constrained by the number of radio channels licensable for their use and by budgets. If either or both of these necessary resources are insutlicient, their data throughput requirements can not be fully satisfied. The method described herein reassigns channels other- wise intended for transferring data in the outbound direc- tion, for carrying data inbound. By redeploying one or more "base station transmit" frequencies in the reverse direction, additional inbound capacity is available with- out licensing additional channels. In effect, throughput 'requirements can be satisfied with fewer channels (fre- quency pairs), and at less cost.

  The method involves the sharing of one or more des- ignated outbound frequencies by two or more (i.e., a greater number of) inbound frequencies, To provide Digital Sense Multiple Access (DSMA), controlled-contention operation, each common outbound channel message must carry status information (channel is "busy" or "free") for each of its associated multiple inbound channels. This will allow each remote terminal to use its respective assigned or automatically selected (see below) inbound channel, while minimizing the probability for message collisions with those from terminals transmitting simultaneously.

The method represents an extension to a technique introduced in Motorola's proprietary MDC series sig

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nalling data transmission standard. In that system, a seg- ment within each and every channel data block of a physical message is reserved for indicating to the receiv- ing terminal the state of the paired inbound channel, either "busy" or "free:' This new method requires that the state of two or more inbound channels be coded in the channel data block segment or equivalent. Decoding facileness and immunity to, and/or significance of, occa- sional random noise-induced bit errors are design imple- mentation issues.

  In the most basic implementation, the role of the shared outbound channel is simply to control the flow o...