Semi-Persistent Scheduling Assignment Validation via Virtual CRC Extension

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Solution Overview

Problem

In communication systems, particularly in 3GPP E-UTRA LTE, there is a need to reduce the probability of false positive Semi-Persistent Scheduling (SPS) activations in User Equipment (UEs) to avoid interference and maintain communication reliability, while also minimizing the decoding operations and power consumption, without increasing the Cyclic Redundancy Check (CRC) size.

Innovation Solution

The solution involves reducing the dynamic range of certain Information Elements (IEs) in Scheduling Assignments (SAs) for SPS, setting specific bits to predetermined values to virtually extend the CRC, thereby reducing the probability of false SPS activations. This is achieved by identifying IEs that are not essential for SPS services like VoIP and setting their bits to fixed values, maintaining the same physical CRC size, and ensuring that SPS SAs and dynamic SAs have the same size to minimize decoding operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the CRC size is increased to reduce false positive SPS activations, then the reliability is improved, but the overhead and complexity increase

Engineering Contradiction:

Improvefalse positive SPS activation probabilityVSAvoidCRC size

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the parameter values of specific Information Elements (IEs) in the SPS SA by setting their bits to predetermined values, effectively using these fixed-value bits as virtual CRC extensions. This approach reduces false positive activations without increasing the actual CRC size, as the fixed IE bits serve as additional validation bits.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent makes the Information Elements serve dual purposes: conveying scheduling information when needed and acting as virtual CRC bits when set to predetermined values. This multi-functionality allows the same field to provide both data transmission and error detection functions without requiring separate dedicated bits.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If the dynamic range of IEs is reduced to extend virtual CRC, then the reliability is improved, but the adaptability deteriorates

Engineering Contradiction:

Improvefalse positive SPS activation probabilityVSAvoidIE dynamic range

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies different properties to different parts of the SA message: specific IEs (such as MCS, PRB allocation, HARQ process) are set to fixed predetermined values to serve as virtual CRC bits, while other IEs maintain their full dynamic range for normal scheduling flexibility. This local differentiation allows reliability improvement in critical fields without sacrificing overall system adaptability.

Inventive Principle:

Principle #3Local quality

3Productivity

If the SA size is kept uniform to minimize decoding operations, then the productivity is improved, but the information capacity is reduced

Engineering Contradiction:

Improvedecoding operationsVSAvoidinformation capacity

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The patent uses a uniform SA size structure where certain fields are allocated more bits than strictly necessary for their information function, with the excess bits set to fixed predetermined values. This allows the SA to maintain a consistent size for efficient UE decoding while the predetermined bits serve as virtual CRC extensions, effectively using partial bit capacity for error detection rather than information transmission.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS11317434B2Method and apparatus for processing scheduling assignments in a communication system

Publication Date: 2022.04.26 UNWIRED PLANET INT LTD

AI summary

A determination is made whether each predetermined bit of a plurality of predetermined bits of a Semi-Persistent Scheduling (SPS) scheduling assignment for a user equipment (UE) has a respective predetermined value required to validate the SPS scheduling assignment. In circumstances where each predetermined bit of the plurality of predetermined bits of a Semi-Persistent Scheduling (SPS) scheduling assignment is determined to have a respective predetermined value required to validate the SPS scheduling assignment, an action corresponding to SPS is performed. In circumstances where at least one predetermined bit of the plurality of predetermined bits of an SPS scheduling assignment is determined to fail to have a respective predetermined value required to validate the SPS scheduling assignment, the SPS scheduling assignment is discarded and the action is not performed.