Browse Prior Art Database

DATA PREAMBLE REGISTRATION SERVICE PROCEDURE

IP.com Disclosure Number: IPCOM000007969D
Original Publication Date: 1997-Mar-01
Included in the Prior Art Database: 2002-May-09
Document File: 2 page(s) / 93K

Publishing Venue

Motorola

Related People

Dennis Dybowski Jr.: AUTHOR

Abstract

In an APCO 25 compliant integrated digital voice/data conventional radio system, scanning data messages (Figure 1) is difficult because the most important information of the data message is in the first part of the message (Figure 2). This part of the data message must be received in its entirety to suc- cessfully receive the message. In order to make scanning data messages easier a preamble can pre- cede the message. However, adding this preamble to all data messages will reduce the system's data throughput. Note that all values are approximate.

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MOTOROLA Technical Developments

DATA PREAMBLE REGISTRATION SERVICE PROCEDURE

by Dennis Dybowski Jr.

INTRODUCTION data message must be received in its entirety to suc-

  In an APCO 25 compliant integrated digital cessfully receive the message. In order to make voice/data conventional radio system, scanning data scanning data messages easier a preamble can pre- messages (Figure 1) is difficult because the most cede the message. However, adding this preamble important information of the data message is in the to all data messages will reduce the system's data first part of the message (Figure 2). This part of the throughput. Note that all values are approximate.

Channel

Channel Channel

Channel

Priority

~~~~~e, Sea

Channel Sea

Change 1 st Non-priority Change Change . . .

1 Channel Scan 1 I

Sea

7 I

I

I I I I

15ITlS 8ms 15ms 8ms 15ms 8ms

Fig. 1 Typical Subscriber Scan Pattern

5ms 6.7ms 20ms

Frame Net Sync ID Header

Data Blocks..

Fig. 2 Start of Data Message

  A better idea would be to have the scan state of messages targeted for scanning subscribers to the subscriber contained in the registration message increase the probability of the subscriber scanning sent to the system's data controller. The data con- the data message.
troller would then add a preamble (Figure 3) to data

FS NID Preamble

Header

Possible Data Blocks to Extend the Preamble Len

ctual Data Messa!

Fig. 3 Data Message with Preamble

0 Motorola, 1°C. 19% 33 March I997

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MOTOROLA Technical Developments

@

  Upon entering scan, the subscriber sends a reg- istration message to the data controller. The mes- sage indicates that the subscriber is scanning and might also contain information about the sub- scriber's scan list and priority channel. This mes- sage is sent out on one...