Wireless Device System Information PLMN Selection
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Solution Overview
Problem
In wireless communication networks, particularly in LTE, the existing methods for system information broadcasting lead to increased latency and energy consumption due to the need for wireless devices to scan multiple frequency carriers for PLMN selection, especially when transitioning between operators or during initial power-on, as they rely on infrequent broadcasts of full system information configurations.
Innovation Solution
Implementing a method where wireless devices receive a compressed first system information indicating supported PLMNs with fewer bits, using checksums, aggregated PLMN IDs, or bloom filters, allowing them to quickly determine if a frequency carrier is accessible, and only receive the full second system information when necessary, reducing the need for frequent broadcasts and minimizing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wireless devices scan multiple frequency carriers to find supported PLMNs during initial access, then the device can ensure it finds an allowed PLMN, but the access time and energy consumption increase significantly
Solution Approach 1:
The system information is segmented into two parts: a compressed first system information (e.g., using bloom filters, checksums, or aggregated PLMN IDs) that can be quickly decoded to determine if a PLMN is supported, and a complete second system information that provides full PLMN lists. This segmentation allows devices to quickly filter unsuitable frequency carriers without processing complete system information, significantly reducing access time while maintaining reliable PLMN selection.
2Loss of information
If wireless devices receive complete system information configurations frequently, then they can always have up-to-date PLMN information, but the energy consumption and network interference increase
Solution Approach 1:
The patent extracts the essential PLMN identification functionality from the complete system information configuration. Instead of transmitting full system information configurations frequently, the network transmits only compressed PLMN indicators (first system information) that enable devices to determine PLMN support. This extraction reduces the amount of data that needs to be transmitted and processed, lowering energy consumption and network interference while maintaining sufficient information freshness for PLMN selection.
3Speed
If the network broadcasts full system information configurations frequently, then wireless devices can quickly access accurate PLMN data, but the network interference and energy consumption increase
Solution Approach 1:
The patent applies different information densities to different needs: compressed first system information is transmitted frequently for quick PLMN suitability checks, while complete second system information is transmitted less frequently for devices that need full configuration details. This local quality approach optimizes the balance between information access speed and network interference by providing just enough information at the right frequency without overwhelming the network channel.
Data Source
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AI summary
A method performed by a wireless device (121) for receiving system information from a network node (110) in a wireless communications network (100) is provided. The wireless device first receives a first system information indicating one or more Public Land Mobile Networks, PLMNs, supported on a frequency carrier by the network node (110). Then, the wireless device determines if the one or more PLMNsindicated in the first system information exclude all PLMN(s) supported by the wireless device (121). When the one or more PLMNsindicated in the first system information does not exclude all PLMN(s) supported by the wireless device (121), then the wireless device receives a second system information comprising the one or more PLMNs supported on the frequency carrier by the network node (110). A wireless device (121) for receiving system information is also provided. Further, a network node and a method therein for transmitting system information are also provided.