Variable-Rate Block Encoding for LTE Control Signal BLER
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Solution Overview
Problem
In LTE cellular networks, existing technologies face challenges in efficiently transmitting control signals, such as CQI reports, on data channels due to differences in operation between control and data channels, which affect error protection and reception quality, especially for cell-edge user equipment.
Innovation Solution
A method and device for user equipment in LTE systems that block encode control signals with a variable rate block code matching the data channel's coding rate, allowing control signals to be transmitted over data channels with appropriate error protection, ensuring target BLERs are met for both control and data channels, and using cyclically repeated block codes to achieve this.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control signals are transmitted on the data channel using conventional control channel encoding, then the control signal structure is maintained, but the transmission reliability deteriorates under poor channel conditions
Solution Approach 1:
The patent applies dynamics by making the block code rate variable rather than fixed. The encoder adapts the coding rate based on channel conditions and data channel requirements, transforming a static encoding system into a dynamic one that can respond to changing transmission environments, thereby resolving the contradiction between maintaining control signal structure and adapting to poor channel conditions
Solution Approach 2:
The patent changes the coding rate parameter of the block code to match the data channel's coding rate. This parameter adjustment allows the control signal encoding to adapt to the data channel's characteristics and channel conditions, improving transmission reliability while maintaining compatibility with the data channel structure
2Reliability
If a fixed block code is used for control signals on the data channel, then the encoding structure is simple, but the target BLER cannot be achieved under varying channel conditions
Solution Approach 1:
The patent transforms the fixed block code into a variable rate block code that can dynamically adjust its coding rate. This dynamic adjustment capability enables the system to achieve target BLER under varying channel conditions while maintaining a relatively simple encoding structure based on the familiar block code framework
Solution Approach 2:
The variable rate block code serves multiple functions: it encodes control signals while adapting to different channel conditions, matches the data channel coding rate, and maintains compatibility with existing block code structures. This multi-functionality achieves target BLER without significantly increasing encoding complexity
3Productivity
If the control channel encoding scheme is copied to the data channel, then the control signal structure is preserved, but the transmission efficiency deteriorates due to mismatched coding rates
Solution Approach 1:
The patent changes the coding rate parameter of the block code to match the data channel's coding rate. This parameter alignment improves transmission efficiency by eliminating the mismatch between control and data channel encoding, while the block code structure itself preserves control signal integrity
Solution Approach 2:
The patent creates a composite encoding approach by combining the block code structure (which preserves control signal characteristics) with a variable rate mechanism (which matches data channel coding rate). This composite solution achieves both transmission efficiency and control signal integrity
Data Source
AI summary
A control channel encoder includes a determiner configured to determine a current value of K for encoding control signals of a length M, wherein K is a function of a code rate for a data channel. A table generator is configured to, if K is greater than a predetermined threshold, generate a repeated matrix from a fixed block encoding matrix by variably repeating rows from said fixed block encoding matrix. A puncturer is configured to, if K is less than the predetermined threshold, puncture the fixed block encoding matrix to reduce a size of the fixed block encoding matrix. A block encoder is configured to utilize said repeated matrix, to encode M input control bits as K encoded control bits, by generating an encoded payload from said repeated matrix.