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Method of Accurate Replay of GSM/GPRS Protocol Stack Execution

IP.com Disclosure Number: IPCOM000130508D
Publication Date: 2005-Oct-25
Document File: 3 page(s) / 13K

Publishing Venue

The IP.com Prior Art Database

Abstract

This invention is to enable accurate duplication or replay of the protocol stack execution for GSM/GPRS Mobile Stations.

This text was extracted from a Microsoft Word document.
This is the abbreviated version, containing approximately 46% of the total text.

PROTOCOL STACK EXECUTION

Method of Accurate Replay of GSM/GPRS Protocol Stack Execution

Disclosed Anonymously

This invention is to enable accurate duplication or replay of the protocol stack execution for GSM/GPRS Mobile Stations.

Although most mobile manufacturers have various protocol stack logging software to record and display information regarding the protocol stack execution for analysis, it is hard to identify the problem if complicated processing inside a single thread is involved or of the problem is due to a layer 1 interrupt handler because this kind of protocol stack logging normally just records message/primitive exchange between different threads, instead of inside a thread or between a thread and an interrupt handler. As a result, to identify the root cause under this situation, developers need to add debug information based on their judgment, make a test build, and then run the scenario again.  This procedure may be repeated over and over.  This procedure is inefficient and even impractical when the scenario is hard to repeat or the test is performed in a remote location. To address this issue, an effective solution is designed to record relevant information to the PC and replay the scenario as many times as wanted on different firmware builds and different mobile stations. Since recording of network downlink data is at the the boundary between L1 interrupt handler and the DSP, the execution sequence from layer 3 down to layer 1 (excluding DSP software) of the protocol stack can be replayed and debugged.

The proposed solution consists of several functional modules.

1. PC-based data upload/download software -

This is a PC application to download (from the mobile station to the PC) or upload (from the PC to the mobile station) the logged data. In addtion, it provides a command to switch the mobile station between the LOGGING mode and the REPLAY mode.

2. Switch between the LOGGING mode and the REPLAY mode -

There are two operation modes. With a command sent from the PC logging software, the mobile station can be configured as either LOGGING mode or REPLAY mode. In LOGGING mode, the device saves the varying data sequentially into a block of dedicated memory; in REPLAY mode, the device loads the varying data sequentially when the they are referred to.  The default mode upon switch-on is LOGGING mode so that data logging can start before the PC-based upload/download software is connected to the mobile station. This enables postmortem analysis.

3. Record relevant information in a compact way -

To be able to replay the scenario accurately, we need to record all relevant variables. In light of the limited memory space and processor speed in a typical embedded device, we need to record variables only related to the protocol stack and in a compact way. There are multiple inputs to control the execution sequence of the protocol stack as a whole. Some are at the boundary of the protocol stack, such as the requests from the application l...