Turbo Coding for Large CQI/PMI Payloads in LTE Uplink
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Solution Overview
Problem
The increasing size of Channel Quality Indicators (CQI) and Precoding Matrix Indicators (PMI) payload in LTE Rel-10 systems poses inefficiencies in transmission, particularly due to the limitations of convolutional coding, which is not effective for larger payload sizes, leading to increased overhead and reduced resources available for data transmission.
Innovation Solution
Implementing turbo coding for CQI/PMI information when the payload size exceeds a certain threshold, along with setting a separate beta offset value for turbo coding, allows for more accurate resource allocation and efficient transmission by matching the code rate of CQI/PMI with that of UL-SCH data, thereby optimizing resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If convolutional coding is used for CQI/PMI information, then the transmission is compatible with existing LTE Rel-8 standards, but the coding efficiency deteriorates when payload size exceeds certain threshold
Solution Approach 1:
The patent implements dynamic selection of coding schemes based on payload size. For CQI/PMI payloads above a threshold, turbo coding is applied; for smaller payloads, convolutional coding is used. This dynamic adaptation resolves the contradiction by optimizing coding efficiency for large payloads while maintaining standard compatibility through conditional application of different coding schemes.
Solution Approach 2:
The patent changes the coding parameter (coding scheme type) based on the payload size parameter. When the CQI/PMI payload exceeds a configured threshold, the system switches from convolutional coding to turbo coding, thereby adapting the coding parameter to match the payload characteristics and improve coding efficiency for large payloads.
2Measurement precision
If separate beta offset value is configured for turbo coding, then the resource allocation accuracy for CQI/PMI improves, but the system complexity increases
Solution Approach 1:
The patent applies local quality by configuring a separate beta offset value specifically for turbo-coded CQI/PMI information, rather than using a universal offset for all coding schemes. This localized configuration improves resource allocation accuracy for turbo coding without requiring complete reconfiguration of the system, thereby balancing precision improvement with acceptable complexity increase.
Solution Approach 2:
The patent implements partial action by introducing a separate beta offset only for the specific case of turbo-coded CQI/PMI, rather than creating separate offsets for all possible coding scenarios. This partial differentiation provides the necessary precision for turbo coding while avoiding the excessive complexity that would result from comprehensive parameter separation across all coding schemes.
3Measurement precision
If CQI/PMI payload size is increased to provide more channel status information, then the channel status reporting precision improves, but the overhead increases and reduces resources available for data transmission
Solution Approach 1:
The patent replaces the mechanical constraint of fixed resource allocation with an adaptive coding system. By substituting convolutional coding with turbo coding for large payloads, the system achieves better compression efficiency and lower overhead for the same amount of CQI/PMI information, thereby reducing the resource cost of high-precision channel status reporting.
Solution Approach 2:
The patent changes the coding efficiency parameter by switching to turbo coding for large CQI/PMI payloads. This parameter change reduces the overhead required to transmit the same amount of channel status information, allowing higher reporting precision without proportionally increasing the resources consumed.
Data Source
AI summary
Methods, for use in a communications system, for transmitting information that applies a method for channel coding the CQI/PMI information, wherein a turbo coding method is applied when the size of the CQI/PMI information is above a first threshold value. The methods further include setting, based on the method applied for the channel coding, an offset value indicative of the difference in code rate between the code rate of the CQI/PMI information and the assigned code rate of the UL-SCH data information on the PUSCH. The methods also include determining, based on the offset value, the number of coded bits to be used for transmission of the CQI/PMI information, and transmitting the CQI/PMI information to a radio access network node on resources assigned based on the determined number of coded bits.