Cell reselection for improving network interconnection

Abstract

This invention describes a new methodology for a cell reselection by a mobile station (MS) for improving network interconnection and interoperability in a limited mobile access environment. The invention is applicable to any kind of networks and their interconnections. The invention describes how the MS can better recover from failed intersystem cell reselection attempts so that there are fewer subsequent failed attempts using two major improvements. First, the MS takes into consideration during cell reselection evaluation and candidate-cell selection, whether the MS had previously been unsuccessful in reselecting the considered cell. This means treating neighbor cells to which the MS had failed reselection before with a lower priority in subsequent cell reselection evaluations. Second, the MS is allowed to stop monitoring and thus, to stop evaluating cells if it was earlier found that the access to those cells is forbidden.

Description

[0001] Cross References to Related Applications [0002] This application claims priority to US Patent Application Serial No. 10 / 970827, filed October 20,2004. technical field [0003] The present invention relates generally to mobile communications and more particularly to cell reselection for improved network interconnection and interoperability. Background technique [0004] The current problem faced by a GSM-UTRAN capable MS (Mobile Station) roaming in a GSM-UTRAN (Global System for Mobile Communications - Universal Terrestrial Radio Access Network) network environment is twofold. One aspect is that the MS may keep trying to reselect the same cell (eg UTRAN cell) that has been found to be unsuitable. Another aspect is that the MS wastes energy by monitoring unreachable cells. Both scenarios are described below. [0005] The first situation is when the MS tries to reselect the same unsuitable cell (eg, UTRAN cell). Currently, MSs with inter-RAT (Radio Access Technolog...

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Problems solved by technology

Thus, the prior art does not provide any guidance on how the MS handles the situation

[0007] The second scenario is when the MS wastes energy by monitoring forbidden cells (e.g. UTRAN cells)

In order to check these, the MS needs to receive the system information message of the target cell, for a shared GSM / WCDMA RF receiver hardware implementation, this may cause short gaps in service availability

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