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METHOD OF IMPROVING CHANNEL THROUGHPUT BY TRANSMITTING MULTIPLE DATA PACKETS PER CHANNEL ACCESS INVOCATION

IP.com Disclosure Number: IPCOM000009482D
Original Publication Date: 1999-Sep-01
Included in the Prior Art Database: 2002-Aug-28
Document File: 1 page(s) / 74K

Publishing Venue

Motorola

Related People

Stan Knapczyk: AUTHOR

Abstract

AFCO Project 25 Common Air Interface (CAI) specifications call for use of the Digital Slotted Multiple Access (DSMA) method for subscriber radio inbound data traffic. This DSMA method defines a protocol to be used for channel access that minimizes collisions on the inbound channel. To be effective in avoiding collisions, the DSMA method requires that a subscriber unit, with a data packet queued for transmission, check the status of the channel and only transmit if the inbound channel is IDLE.

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Developments Technical 0 M MOTOROLA

METHOD OF IMPROVING CHANNEL THROUGHPUT BY TRANSMllTlNG MULTIPLE DATA PACKETS

PER CHANNEL ACCESS INVOCATION

by Stan Knapczyk

BACKGROUND

  AFCO Project 25 Common Air Interface (CAI) specifications call for use of the Digital Slotted Multiple Access (DSMA) method for subscriber radio inbound data traffic. This DSMA method defines a protocol to be used for channel access that minimizes collisions on the inbound channel. To be effective in avoiding collisions, the DSMA method requires that a subscriber unit, with a data packet queued for transmission, check the status of the channel and only transmit if the inbound channel is IDLE.

  If the inbound channel is busy, the subscriber is required to go to a BUSY wait state where it stops monitoring the channel status for some random peri- od of time. When the period time elapses, the sub- scriber radio polls the channel status again. If still busy, the subscriber radio returns to the BUSY wait

state.

  This continues until an IDLE channel status is seen and the data packet is transmitted. As a result, a subscriber radio with many data packets to send must check the channel status prior to transmitting each data packet and may spend much time in the BUSY wait state. This may result in an inefficient transfer of data packets across an active channel.

SOLUTION

  In Motorola's APCO project 25 integrated voice/data systems, the maximum data packet size is limited to 512 octets. This is done for two reasons. Fist, it assures voice transmissions are not delayed

excessively due to long data transmissions. Voice transmissions are typically...