NB-IoT Modem Memory Allocation for iSIM Provisioning
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Solution Overview
Problem
The integration of a Universal Integrated Circuit Card (UICC) with a Subscriber Identity Module (SIM) in Narrowband Internet of Things devices requires separate secure hardware, increasing system costs and energy consumption due to the need for dedicated memory and chip area.
Innovation Solution
A method that allocates a portion of the modem's dedicated memory to the integrated Subscriber Identity Module (iSIM) during provisioning, allowing for secure reuse and subsequent cleanup by a protection hardware block, reducing the need for dedicated iSIM memory and thus minimizing chip size and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate UICC chip is integrated with the modem chip, then security and identity management functionality is improved, but chip area and system cost increase
Solution Approach 1:
The patent merges the UICC chip and modem chip into a single integrated chip structure. The UICC functionality is implemented as a separate functional module within the same chip package, sharing common resources including memory. This integration maintains security functionality while reducing overall chip area compared to completely separate chips.
Solution Approach 2:
The patent implements a shared memory resource that serves multiple functions: dedicated memory for the UICC module during normal operation, and reusable memory during provisioning mode. This multi-functional memory allocation allows the same physical memory to support both security operations and provisioning operations at different times, reducing the total memory capacity needed.
2Ease of operation
If dedicated memory is allocated to the iSIM during provisioning, then provisioning functionality is improved, but memory utilization efficiency deteriorates
Solution Approach 1:
The patent implements dynamic memory allocation where the memory assigned to the iSIM changes based on operational mode. During normal operation, a first portion of memory is allocated to the iSIM. During provisioning operations, a second (larger) portion of memory is allocated to the iSIM. This dynamic reallocation ensures adequate memory for provisioning while maximizing memory utilization efficiency across different operational states.
Solution Approach 2:
The patent enables temporary allocation of additional memory to the iSIM during provisioning operations, with the understanding that this memory will be released and returned to the modem after provisioning completes. This temporary borrowing of memory resources allows provisioning functionality to proceed without permanently reducing the memory available to the modem for its normal operations.
3Ease of manufacture
If the UICC is integrated into the modem chip, then system cost is reduced, but energy consumption increases
Solution Approach 1:
The integration of UICC and modem into a single chip reduces overall system cost by eliminating the need for separate chip packages, inter-chip connections, and additional mounting hardware. However, the patent addresses the energy concern through selective operational modes where the UICC functionality can be activated only when needed, allowing the integrated structure to remain while minimizing continuous energy consumption.
Solution Approach 2:
The patent implements periodic or on-demand activation of the UICC module within the integrated chip. Rather than continuously powering all components, the system activates UICC-specific functionality only during authentication or provisioning operations, reducing average energy consumption while maintaining the cost benefits of integration.
4Area of stationary object
If memory is shared between modem and iSIM, then chip area is reduced, but security risk increases
Solution Approach 1:
The patent segments the shared memory into distinct logical portions: a first portion dedicated to the UICC module and a second portion for the modem. This segmentation is enforced through controlled access mechanisms where each module can only access its designated memory portion during normal operation. The segmentation maintains security boundaries while allowing physical memory sharing to reduce chip area.
Solution Approach 2:
The patent introduces a memory management intermediary that controls access to the shared memory resource. This intermediary enforces access rules, ensuring that the modem cannot read or write to the UICC's dedicated memory portion and vice versa. The intermediary acts as a security gatekeeper, enabling memory sharing while preventing unauthorized access and maintaining security isolation between the two functional modules.
Data Source
AI summary
A method for improving memory utilization of a Narrowband Internet of Things device (UE) is provided. The method includes: switching the modem to a provisioning mode and allocating a portion of the dedicated memory of the modem during provisioning of the iSIM on the modem chip of the UE; reusing, by the iSIM, the portion of the dedicated memory of the modem for processing provisioning data; securely cleaning up the allocated portion of the dedicated memory of the modem by a protection hardware block after leaving the provisioning mode; and allocating the portion of the dedicated memory of the modem shared with the iSIM back to the modem.