Browse Prior Art Database

DYNAMIC OVER THE AIR DATA COMPRESSION

IP.com Disclosure Number: IPCOM000008189D
Original Publication Date: 1997-Jun-01
Included in the Prior Art Database: 2002-May-24
Document File: 2 page(s) / 87K

Publishing Venue

Motorola

Related People

Tom Klein: AUTHOR

Abstract

Today, the paging market is suffering from the lack of airtime in which to transmit messages. A method is needed to reduce the redundant portions of messages which are transmitted. This method suggests a flexible method of compression by the paging terminal which the pager then decompresses upon message reception. A desirable feature of this method of compression is to have the decompres- sion scheme independent of the paging protocol, i.e. FLEX, POCSAG, etc.

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0 M M-LA

Technical Developments

DYNAMIC OVER THE AIR DATA COMPRESSION

by Tom Klein

1 INTRODUCTION

  Today, the paging market is suffering from the lack of airtime in which to transmit messages. A method is needed to reduce the redundant portions of messages which are transmitted. This method suggests a flexible method of compression by the paging terminal which the pager then decompresses upon message reception. A desirable feature of this method of compression is to have the decompres- sion scheme independent of the paging protocol, i.e. FLEX, POCSAG, etc.

2 BACKGROUND

  Pagers have traditionally received data at a slow rate (512-2400 bps). The pager receives a character (typically '7 bits for alpha/idea and 4 bits for numeric) with no data compression. The types of message data has increased from numeric to personal alpha and information (sports, stocks, weather, etc.), and email. This places a burden upon the paging transmitters to keep up with the amount of data which can be transmitted in a timely fashion. With the increase in the number of paging subscribers this situation will continue to degrade Alternatives are to increase the data throughput rate, limit the amount of data being transmitted, increase the

number of channels for receiving data, or compressing the data being transmitted.

  Data compression is a common technique today, already used on personal computers and digital voice compression.

3 PROPOSED IMPLEMENTATION

  The method of compression has the paging terminal search the data stream for repeating patterns, prior to message transmittal. These patterns are then replaced by a token that is not present in the data stream. This token and the data it replaces is sent at the beginning of the message. Mult...