Turbo Decoder Recursion Scheduling for Flexible Iteration Initialization
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Solution Overview
Problem
Turbo decoders implemented in integrated circuit devices have limited decoding versatility, necessitating a more versatile approach to improve receiver performance in terms of bit error rate and frame error rate.
Innovation Solution
A bi-modal Turbo decoder is introduced, allowing selection between a first mode with a limited number of iterations for backward recursion initialization and a second mode with a higher number of iterations for Next Iteration Initialization, enabling flexible scheduling of recursion units to enhance decoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single fixed initialization mode is used in the Turbo decoder, then the initialization process is simple, but the decoding versatility and performance are limited
Solution Approach 1:
The patent implements a bi-modal Turbo decoder that can dynamically switch between two initialization modes (acquisition recursion mode and next iteration initialization mode) based on operating conditions. The scheduler dynamically selects which mode to use, allowing the decoder to adapt to different scenarios such as first transmission versus retransmission, thereby improving decoding versatility without requiring a completely separate decoder for each mode
Solution Approach 2:
The same Turbo decoder structure is designed to perform multiple initialization functions by selecting between two modes. The acquisition recursion mode is used for certain initialization scenarios while next iteration initialization is used for others, allowing a single universal decoder to handle diverse decoding requirements including different transmission types and retransmission scenarios
2Reliability
If recursion units are scheduled for acquisition recursions, then initialization is performed, but the number of iterations available for actual decoding is reduced
Solution Approach 1:
The scheduler dynamically adjusts the allocation of recursion units between acquisition recursions and actual decoding iterations based on the operating mode. In acquisition recursion mode, recursion units are scheduled for initialization to ensure reliability. In next iteration initialization mode, recursion units are allocated to actual decoding iterations to maximize throughput. This dynamic scheduling resolves the contradiction by making the system adaptive to different operational requirements
3Measurement precision
If the number of iterations is increased for better initialization, then decoding accuracy improves, but latency increases
Solution Approach 1:
The patent changes the initialization parameter by offering two distinct modes: acquisition recursion mode which uses fewer iterations but schedules recursion units for initialization, and next iteration initialization mode which uses more iterations without dedicated initialization scheduling. This parameter change allows the system to trade off between accuracy and latency based on the selected mode, resolving the contradiction by making the trade-off adjustable rather than fixed
Data Source
AI summary
An embodiment of a decoder is disclosed. For this embodiment of the decoder, a first estimation unit and a second estimation unit are for iterative decoding. A scheduler is to receive a mode select signal to provide either an indication of first scheduling information or second scheduling information to the first estimation unit and the second estimation unit responsive to the mode select signal.