Browse Prior Art Database

RELIABLE DATA LAYER SESSION BASED IN AN RF PACKET NETWORK SYSTEM

IP.com Disclosure Number: IPCOM000008150D
Original Publication Date: 1997-Jun-01
Included in the Prior Art Database: 2002-May-22
Document File: 2 page(s) / 95K

Publishing Venue

Motorola

Related People

Rod Averbuch: AUTHOR [+3]

Abstract

In order to overcome a high BER condition over the air in an RF packet network, a best effort data layer is implemented between the mobile and the base station or packet based data layer session is implemented between the router and the mobile. The best effort technique is a reduced functionality of the reliable data layer for efftciency reasons.

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MOlVROLA Tectinical Developments

RELIABLE DATA LAYER SESSION BASED IN AN RF PACKET NETWORK SYSTEM

by Rod Averbuch, Israel Cimet and Valy Lev

INTRODUCTION

  In order to overcome a high BER condition over the air in an RF packet network, a best effort data layer is implemented between the mobile and the base station or packet based data layer session is implemented between the router and the mobile. The best effort technique is a reduced functionality of the reliable data layer for efftciency reasons.

  First the packet is announced by the cell and then it is divided into smaller blocks that are trans- mitted over the air. A bit mapped or frame acknowl- edgment followed by the re-transmission of the bad blocks or frame ensuring a reasonable reliability over the air. (please refer to Figure 1 layer 2A and layer 2B).

The reduced data layer scheme is used in order to avoid a high overhead of reliable data layer

session which is applied on every packet in the system. Yet, in a case of a mobile movement out of cell coverage, all the data in the cell buffer is lost and the upper layers are responsible for a lost pack- ets recovery. In order to avoid this problem a packet layer 2 session could be stretched between the router and the mobile. However, this protocol con- figuration introduces a high overhead per packet (please refer to layer 2C).

  The first technique works good with a relatively short packet/session and long time between hand- offs. Yet, in a long session and short time between handoffs (ESMR packet network extension and PCS) best effort layer 2 technique will cause a heavy penalty in data throughput.

  The second technique works OK with a rela- tively large packets due to the small impact of protocol overhead per packet.

nn

: layer 2A : ,

layer 2B

, layer 2C I

Fig. 1

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65 June 1997

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