Browse Prior Art Database

AUTOMATED SYSTEM CHANNEL ACCESS TIMER CALCULATION

IP.com Disclosure Number: IPCOM000007683D
Original Publication Date: 1996-May-01
Included in the Prior Art Database: 2002-Apr-15
Document File: 2 page(s) / 138K

Publishing Venue

Motorola

Related People

Mike Korus: AUTHOR

Abstract

Channel access rules become necessary in dig- ital communication systems that require subscriber access to inbound RF channels. Many digital sys- terns employ DSMA (digital sense multiple access) algorithms. DSMA provides a mechanism to indicate the inbound channel status (busy, idle or unknown) on outbound RF channels. This infor- mation is used by the subscribers to determine the state ofthe inbound channel. Monitoring the inbound channel status allows subscribers to be "polite" to other users. The rate at which status bit indications are sent is called the slot time. Slot time depends on the system delay (i.e. system turn around time of channel status bits). An example is illustrated below.

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MOlVROLA Technical Developments

AUTOMATED SYSTEM CHANNEL ACCESS TIMER ~CALCULATION

                               by Mike Korus BACKGROUND unknown) on outbound RF channels. This infor- mation is used by the subscribers to determine the Channel access rules become necessary in dig- state ofthe inbound channel. Monitoring the inbound ital communication systems that require subscriber channel status allows subscribers to be "polite" to access to inbound RF channels. Many digital sys- other users. The rate at which status bit indications terns employ DSMA (digital sense multiple access) are sent is called the slot time. Slot time depends on algorithms. DSMA provides a mechanism to the system delay (i.e. system turn around time of indicate the inbound channel status (busy, idle or channel status bits). An example is illustrated below.

U = Unknown 72 bits = 7Smsec = uSlot time S = Status of channel (busy or idle)

Slot = 6 uSlot = 45 msec

Slot time = Delay of system (rounded up to next uSlot) Example: Delay of system = 40 msec, 40 / 7.5 = 5.33 ==> 6 uyot I Slot

performance of the system for the following reasons:

  The system delay is used to set the slot time for a given system (usually programmed in a base sta- tion) and is also used to set DSMA timers in subscribers to randomize access to the channel. As can be seen in the above example, the smallest slot time possible on this example system is 7.5 msec, however the system delay forces the slot time to be every 6th uSlot.

During system set-up,, DSMA delay timer values and slot times must be determined based on sys- tem throughput. This is a time consuming and manual task.

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When radios or infrastructure equipment are updated with new software releases that affect sys- tem delay, maintenance is required to update the delay timers for optimal system performance.

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PROBLEM:

  Both the slot time in the station and the DSMA timers in the subscriber are either hard coded in sohware or are adjustble via radio service sotlware. This method of setting up and maintaining the slot times and DSMA timers is not very practical in large systems when multiple sofiware upgrades occur. In particular, it makes it difftcult to optimize the data

  Using periodic synchronization information, sys- tem throughput delays ,are calculated during nor- mal system operation. The throughput delay infor- mation is used to automatically update the channel

DESCRIPTION OF SOLUTION

0 Motoroh. Inc. ,996 112 May 1996

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MOFOROLA Technical Developm...