Limited Buffer Rate-Matching Reference Value Determination

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Solution Overview

Problem

In wireless communications, particularly in the New Radio (NR) standard, there is a challenge in managing peak data rates and coded bit throughput due to limited buffer rate-matching, which can lead to hardware constraints and inefficiencies, especially during retransmissions and numerology switching, where the peak rate may need to be supported at lower code rates than the hardware supports.

Innovation Solution

A method is introduced to determine a reference value X, representing the largest index within a circular buffer for a transport block, which is used to compute data rates and manage encoding and decoding operations, allowing for more flexible and efficient processing without exceeding the coded bit peak rate, thereby accommodating decoding constraints and minimizing scheduler restrictions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If limited buffer rate-matching is applied to limit coded bit throughput, then peak data rate is controlled, but the system cannot accommodate smaller TBS transmitted over smaller durations that yield peak rate at lower code rates

Engineering Contradiction:
Improvepeak data rateVSAvoidflexibility in TBS and duration configuration
Core Design Contradiction:
PowerVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic reference TBS determination where the reference transport block size is adaptively selected based on the actual TBS and transmission duration. The network node dynamically calculates whether to use a first reference TBS (for initial transmission) or a second reference TBS (for retransmission) based on the circular buffer index and transmission characteristics, allowing the rate-matching to adapt to different operational scenarios rather than using a fixed reference value

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter used for rate-matching by introducing a reference circular buffer index that is determined based on the actual TBS and transmission duration. Instead of using a fixed reference TBS, the system dynamically determines a reference circular buffer index from the actual circular buffer index, effectively changing the reference parameter to match the actual transmission conditions and enabling proper rate-matching for smaller TBS over shorter durations

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If reference TBS is used for rate-matching, then coded bit buffer is limited, but the specification does not limit coded bit buffer for smaller TBS transmitted over smaller durations

Engineering Contradiction:
Improvecoded bit bufferVSAvoidpeak rate support at lower code rates
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent implements feedback mechanisms where the network node determines a reference circular buffer index based on the actual circular buffer index and transmission characteristics. This feedback loop ensures that the rate-matching is continuously adjusted based on the actual transmission conditions, maintaining reliable peak rate support across different code rates and transmission scenarios

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary determination of the reference circular buffer index before the actual rate-matching operation. By pre-calculating the reference circular buffer index based on the actual TBS and transmission duration, the system prepares the rate-matching parameters in advance, ensuring that the coded bit buffer is properly limited before transmission occurs, thereby maintaining reliability for peak rate support at lower code rates

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If fixed rate-matching is applied, then scheduler restrictions are minimized, but encoding and decoding operations cannot be clearly specified

Engineering Contradiction:
Improvescheduler restrictionsVSAvoidencoding and decoding operation specification
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent changes the parameter specification by introducing a reference circular buffer index that is dynamically determined based on the actual circular buffer index and transmission characteristics. This parameter change allows the system to maintain clear and unambiguous specification of encoding and decoding operations while adapting to different transmission scenarios, resolving the contradiction between ease of operation and device complexity

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3841692B1Enhancements to limited buffer rate-matching
Publication Date: 2022.06.15 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3841692B1 patent drawingFigure 1
  • EP3841692B1 patent drawingFigure 2
  • EP3841692B1 patent drawingFigure 3

AI summary

Methods and apparatuses are disclosed for buffer rate-matching. In one embodiment, a method for a wireless device (WD) includes determining a reference value, the reference value indicating a largest index corresponding to a bit within a circular buffer for at least one code block of a transport block, the at least one code block having been selected for transmission of the transport block; determining a condition based on the reference value; and based on the condition, performing an action related to processing of one or more code blocks of the transport block.