Browse Prior Art Database

QUICK RF POWER ADJUST FOR WIRELESS PACKET MODEMS SUBSCRIBER DEVICES

IP.com Disclosure Number: IPCOM000007701D
Original Publication Date: 1996-May-01
Included in the Prior Art Database: 2002-Apr-16
Document File: 2 page(s) / 114K

Publishing Venue

Motorola

Related People

Dennis E. Burke: AUTHOR

Abstract

The media access control for Wirelesss Modem subscriber devices, such as Cellular Digital Packet Data products, allows re-transmission ofpackets that were previously corrupted when received by the Base site Receiver. The corruption may be due to inter- ference noise, or weak and fading signal conditions. This invention solves the problem of having to invoke the high-level protocol Microprocessor into the task of increasing subscriber RF transmit power for those packets that require re-transmission.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 50% of the total text.

Page 1 of 2

MOTOROLA Technical Developments

QUICK RF POWER ADJUST FOR WIRELESS PACKET MODEMS SUBSCRIBER DEVICES

by Dennis E. Burke

INTRODUCTION

  The media access control for Wirelesss Modem subscriber devices, such as Cellular Digital Packet Data products, allows re-transmission ofpackets that were previously corrupted when received by the Base site Receiver. The corruption may be due to inter- ference noise, or weak and fading signal conditions. This invention solves the problem of having to invoke the high-level protocol Microprocessor into the task of increasing subscriber RF transmit power for those packets that require re-transmission.

PRESENT DAY SOLmON

  The CDPD open specification Set 405-3.3.4.1 allows any full-duplex Subscriber device to increase its RF transmission power by 8 dB, up to fit11 power, in the event that the Busy/Idle Flag (returned to the Subscriber unit from the Mobile Data Base Sta- tion (MDBS) via the Forward Channel) is still indi- cating "idle" after three successive bursts from the Subscriber Device. If an MDBS "Busy" flag is detected for at least one of the four next successive Subscriber transmission bursts, the Subscriber unit then starts to measure the Block error rate on suc- cessive blocks received from the MDBS. Ifthe Block error rate drops below a configurable threshold parameter for a configurable time parameter, the Subscriber Unit can return to its initial transmit power level.

  The Wireless Modem subscriber unit main Microprocessor, dealing with the Data Link layers of the OS1 sohware stack, would typically adjust the required RF output power of the Wireless Modem by means of a DAC so as to deliver the Subscriber packets, destined for re-transmission, at successively increasing power levels. This method requires exten- sive communication between any processing com- puter (DSP), whose job is to deliver error-free pack- ets via re-transmission, and any higher-level processor (MPU) that computes the required system RF power

link, based on a continuous monitor of an outbound data stream from the Base site. The ability of the MPU to service any resulting interrupt from the DSP and re-program any serial RF power control DAC in the allotted time for the re-transmission can be severely limited.

  In the current CDPD Subscriber platform archi- tecture, the main Microprocessor determines the ini- tial setting of t...