Wireless Device Network Selection Based on Service History

Solution Overview

Problem

Wireless devices face challenges in selecting preferred wireless networks when traveling, especially in foreign countries, due to limited SIM information and the inability to detect preferred networks, leading to potential rejection of Circuit Switched (CS) services despite Packet Switched (PS) service availability, resulting in undesirable situations where users cannot receive CS voice calls or SMS.

Innovation Solution

The method involves a wireless device maintaining information on the type of service previously provided for each network, selecting a network that is less likely to reject CS service while allowing PS service, and prioritizing networks that have previously allowed both CS and PS services, thereby avoiding registration with networks that may reject CS service.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the wireless device randomly selects an available wireless network with strong RSSI when the last registered network is unavailable, then the device can quickly register with an available network, but the selected network may not offer both CS and PS services, resulting in CS service rejection

Engineering Contradiction:

Improvenetwork registration speedVSAvoidCS service availability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The wireless device performs preliminary actions by maintaining a history of service types offered by previously registered networks. Before registering with a new network, the device checks this history to predict whether the network will offer both CS and PS services, thereby avoiding networks that have previously rejected CS service.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by using information from previous network registrations (service types offered, CS service acceptance/rejection) to influence future network selection decisions. The wireless device learns from past experiences and adjusts its network selection behavior accordingly, prioritizing networks that have historically provided both CS and PS services.

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If the wireless device uses a SIM with limited PLMN selector information for network selection, then the device can operate with standard SIM capabilities, but the device cannot identify preferred roaming networks in foreign countries, leading to suboptimal network selection

Engineering Contradiction:

Improvenetwork selection capabilityVSAvoidpreferred network information

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The wireless device performs preliminary actions by maintaining a history of service types offered by previously registered networks. Before registering with a new network, the device checks this history to predict whether the network will offer both CS and PS services, thereby avoiding networks that have previously rejected CS service.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The wireless device enhances its own network selection capability by autonomously maintaining and utilizing a history of service types from previously registered networks. The device does not rely on external assistance or advanced SIM features but instead uses its own stored information to make informed network selection decisions.

Inventive Principle:

Principle #25Self-service

3Reliability

If the managed roamer box rejects CS attach with cause code 17 after determining the foreign network is not preferred, then the wireless device can be directed away from non-preferred networks, but the device may still register with networks that reject PS service or provide incomplete service

Engineering Contradiction:

Improvenetwork service completenessVSAvoidnetwork selection process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The wireless device performs preliminary actions by maintaining a history of service types offered by previously registered networks. Before registering with a new network, the device checks this history to predict whether the network will offer both CS and PS services, thereby avoiding networks that have previously rejected CS service.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The wireless device maintains more information than the standard SIM provides by storing a history of service types from previously registered networks. This excessive information gathering enables the device to make more accurate network selection decisions, prioritizing networks that have historically provided both CS and PS services.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentEP2222121B1System and method of wireless network selection based on service offered

Publication Date: 2012.02.08 BLACKBERRY LTD

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AI summary

Provided is a system and method of wireless network selection based on service offered. The wireless device scans for available wireless networks upon an event triggering registration. If the wireless device determines based on its SIM that none of the available wireless networks are high priority networks for registration, then the wireless device automatically selects an available wireless network for registration based on, for at least one of the available wireless networks that the wireless device previously registered to, whether CS (Circuit Switched) service was rejected but PS (Packet Switched) service was allowed. Next, the wireless device automatically attempts to register with the selected wireless network. In this manner, the wireless device attempts to register with a wireless network that does not reject CS service while allowing PS service. If the wireless device nonetheless registers with such a wireless network, then registration can be reattempted with another available wireless network.