Browse Prior Art Database

Improvements to IOS A1 Global Reset Procedure in CDMA Systems

IP.com Disclosure Number: IPCOM000010929D
Original Publication Date: 2003-Jan-31
Included in the Prior Art Database: 2003-Jan-31
Document File: 6 page(s) / 147K

Publishing Venue

Motorola

Related People

Tom Schlangen: INVENTOR [+4]

Abstract

This paper describes two inventions that improve the operation of the IOS A1 Global Reset Procedure. The first invention provides a two-way handshake mechanism at both the beginning and end of the Global Reset Procedure; one of several benefits is a dramatic reduction in the execution time of the procedure, which increases overall system availability. The second invention provides a mechanism for either the Mobile Switching Center (MSC) or Base Station (BS) to immediately indicate if a fatal incompatibility is detected on the MSC-BS interface; early indication enables the MSC and BS to promptly initiate recovery procedures.

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Improvements to IOS A1 Global Reset Procedure in CDMA Systems

Tom Schlangen, Mohamad Dawood, Doug White, Scott Marin

Abstract

This paper describes two inventions that improve the operation of the IOS A1 Global Reset Procedure. The first invention provides a two-way handshake mechanism at both the beginning and end of the Global Reset Procedure; one of several benefits is a dramatic reduction in the execution time of the procedure, which increases overall system availability. The second invention provides a mechanism for either the Mobile Switching Center (MSC) or Base Station (BS) to immediately indicate if a fatal incompatibility is detected on the MSC-BS interface; early indication enables the MSC and BS to promptly initiate recovery procedures.

Invention #1 – IOS A1 Global Reset Procedure Optimization

This invention describes a method to enhance the currently standardized TIA/EIA/IS-2001-A Global System Reset procedure to reduce the time it takes to initialize the A1 interface, which improves overall system availability. Signaling information is sent via the A1 interface between the Mobile Switching Center (MSC) and Base Station (BS) in order to perform the Global System Reset procedure, and several scenarios are possible:

  1. BS-initiated Global System Reset (see Figure 1)
  2. MSC-initiated Global System Reset
  3. Reset Glare noticed at the BS
  4. Reset Glare noticed at the MSC
  5. Reset Glare noticed at both the BS and MSC (see Figure 2)

For brevity, Scenarios 2-4 and failure scenarios have not been illustrated in this paper.

The invention defines additional A1 messages to allow both the BS and MSC to explicitly declare when initialization procedures have started and completed so that normal operations can begin in the shortest possible time. This mechanism introduces a two-way handshake to initiate the Global System Reset sequence and a two-way handshake to terminate the sequence.

The Global System Reset is initiated by a Reset message being sent from the BS or MSC to its counterpart as currently specified in the TIA/EIA/IS-2001-A standard.� The initial two-way handshake is completed by a Reset Started (new message), which includes IOS Revision Level information. Having the Revision Level information declared by both sides at the start of the procedure is advantageous because future improvements to the standard can leverage that information.

The Reset sequence is terminated by the exchange of a Reset Complete (new message) and a Reset Complete Acknowledge (new message) between the BS and the MSC.� Note that the Circuit Blocking procedure shall occur between the A1 Reset Started handshake and the Reset Complete handshake.� By incorporating the Reset / Reset Started handshake prior to sending any Block message(s), the Circuit Blocking procedure is no longer initiated prematurely (i.e., prior to confirmation of the MSC’s existence).�

Figure 1: “BS-Initiated Global System Reset” illustrates the BS initiating the Global System Reset procedure. The major...