Control Block Masking for Extended TFI in GERAN DLMC

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Solution Overview

Problem

The existing Temporary Flow Identifier (TFI) addressing space in GERAN networks is insufficient, particularly with the introduction of Downlink Multicarrier (DLMC) mode, where legacy mobiles can incorrectly decode FIRE-coded control blocks due to the inability of existing solutions to extend the TFI space effectively.

Innovation Solution

A method involving a wireless device and a radio network node that assigns an extended Temporary Flow Identifier (eTFI) and performs bit-wise modulo two addition with a pre-determined bit pattern, distributed over the shortest uncorrectable burst error length, to create a modified control block that legacy devices cannot decode, ensuring only eTFI-aware devices receive intended control information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the existing TFI addressing space is used in GERAN networks with DLMC mode, then the system can support basic packet switched traffic, but the addressing space becomes insufficient and legacy devices may incorrectly decode control blocks

Engineering Contradiction:
ImproveTFI addressing space capacityVSAvoidcontrol block decoding accuracy
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent extends the TFI addressing space by introducing an extended TFI (eTFI) field that adds additional bits to the original TFI structure. This dimensional extension allows the system to support more devices in DLMC mode while maintaining backward compatibility through a structured field expansion approach

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces a transformation intermediary process that converts the extended TFI (eTFI) into a modified form before inclusion in the control block. This intermediary transformation ensures that legacy devices cannot correctly decode the control blocks intended for eTFI-aware devices, thereby preventing incorrect decoding while allowing the extended addressing space to function properly

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If the TFI field is extended to support more devices in DLMC mode, then the addressing space increases, but legacy devices may still incorrectly decode control blocks due to the extended field structure

Engineering Contradiction:
Improvenumber of supported devicesVSAvoidincorrect decoding by legacy devices
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

A transformation intermediary is applied to the eTFI field before it is placed in the control block. This intermediary process modifies the eTFI values in a controlled manner so that legacy devices, which do not recognize the extended field structure, cannot successfully decode the control blocks. This prevents legacy devices from incorrectly receiving control information while maintaining the extended addressing capability for modern devices

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary anti-action by intentionally designing the eTFI field and its transformation in a way that preemptively prevents legacy devices from correctly decoding control blocks. The modified control block structure with transformed eTFI values creates an inherent incompatibility with legacy decoding logic, thus preventing harmful incorrect decoding before it can occur

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP3355505B1Methods, a wireless device, a radio network node for managing a control block
Publication Date: 2020.07.29 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3355505B1 patent drawingFigure 1~2
  • EP3355505B1 patent drawingFigure 3~4
  • EP3355505B1 patent drawingFigure 5~6

AI summary

Methods, a wireless device (110) and a radio network node (120) for managing a control block are disclosed. An extended Temporary Flow Identifier, eTFI, is assigned to the wireless device (110) by the radio network node (120). The radio network node (120) constructs the control information. The radio network node (120) performs a bit-wise modulo two addition with a control block and a combination of the eTFI and a pre-determined bit pattern to obtain a modified control block. The radio network node (120) adds channel coding redundancy. The radio network node (120) maps the modified control block onto physical resources. The radio network node (120) sends the modified control block to the wireless device (110). The wireless device (110) decodes the received modified control block removing the channel coding redundancy, performs a bit-wise modulo two addition between the modified control block and a combination of the eTFI and a pre-determined bit pattern to obtain a control block. The wireless device (110) decodes the control block using FIRE-decoding to obtain the control information. The wireless device (110) determines it is the intended recipient of the control information if the TFI information therein matches its assigned TFI. Corresponding computer programs and carriers therefor are also disclosed.