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Method of establishing communication channel between handsets and network-based servers

IP.com Disclosure Number: IPCOM000013139D
Original Publication Date: 2003-Jun-16
Included in the Prior Art Database: 2003-Jun-16
Document File: 7 page(s) / 405K

Publishing Venue

Motorola

Related People

Derek Oxley: INVENTOR [+5]

Abstract

This invention enables a network server to determine the need for a secondary in-band communication channel in addition to a signaling channel with clients and the means to establish them. The secondary channel applies different Quality Of Service (QoS) to the data types within this channel (user data and in-band signaling). The server determines the extent of signaling for the call and this is effected over a secondary signaling channel within the traffic channel (TCH) with an enhanced QoS for the in-band signaling. In one embodiment, the channel is essentially application level messages over the Internet Protocol (IP), making it an efficient method of communication. In another embodiment, the SIP INFO messages are used to encapsulate and carry these messages. This mechanism was introduced in support of Dispatch Services in CDMA 1X networks. The Dispatch Applications Server accepts and processes Dispatch and other service requests from handhelds and Mobile Stations (MS). The server and the MS communicate on the specified communication channel, independent of normal signaling for call processing. The invention proposes one method of establishing this communication channel using SIP signaling, while meeting the stringent requirement of a 1500 ms call setup delay.

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Method of establishing communication channel between handsets and network-based servers

Derek Oxley

Nandakishore Anant Albal

Peter Armbruster

William Shores

Bradley Schaefer

I.                   Abstract

This invention enables a network server to determine the need for a secondary in-band communication channel in addition to a signaling channel with clients and the means to establish them.

The secondary channel applies different Quality Of Service (QoS) to the data types within this channel (user data and in-band signaling). The server determines the extent of signaling for the call and this is effected over a secondary signaling channel within the traffic channel (TCH) with an enhanced QoS for the in-band signaling. In one embodiment, the channel is essentially application level messages over the Internet Protocol (IP), making it an efficient method of communication. In another embodiment, the SIP INFO messages are used to encapsulate and carry these messages.

This mechanism was introduced in support of Dispatch Services in CDMA 1X networks. The Dispatch Applications Server accepts and processes Dispatch and other service requests from handhelds and Mobile Stations (MS). The server and the MS communicate on the specified communication channel, independent of normal signaling for call processing. The invention proposes one method of establishing this communication channel using SIP signaling, while meeting the stringent requirement of a 1500 ms call setup delay.�

II.                Introduction

This invention enables the establishment of a secondary communication channel between a server in the infrastructure and the handset (client) over which the client and server can communicate. This secondary communication channel shares the Traffic Channel that carries user and application data with different QoSs. Though the secondary communication channel is triggered by the initial call-request, it is independent of the call-related signaling. The server determines the need for this secondary channel (e.g. authentication, group-call addresses, etc.) on reception of the initial call request and initiates its establishment.

III.             Background, Market Need and Problem Statement

Currently, the iDEN network provides dispatch services for carriers such as Nextel are based on modified TDMA technology.� Nextel would like to deploy dispatch services over a CDMA infrastructure and take advantage of its RF efficiencies, and ride the technology curve by using IP technology in their infrastructure and use SIP as the preferred signaling protocol to the handsets. In addition Nextel desired to have an open-architecture that would enable them to procure the RF and signaling infrastructures (signaling server in the figure) from different vendors.

This raises multiple issues, two of the most significant ones are:

  • The limited bandwidth that exists on the CDMA signaling/access channel (RF)

·        The ASCII based SIP signaling protocol is verbose and was designed for traditional land-based large bandwidth signa...