PCFICH Coding With Repeated 3-Bit Codewords for Uneven Lengths
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Solution Overview
Problem
Current methods for coding the CCFI channel are inadequate when the total coded length is not an integer multiple of three, as they rely on (3,2) codewords that are only suitable for integer multiples of three, leading to inefficiencies in transmit diversity schemes for dynamic Category 0 bits and ACK/NACK channels in wireless communication systems.
Innovation Solution
A method involving the concatenation of repeated (3,2) codewords and uncoded CCFI bits is proposed, where a length-3 component codeword is repeated and concatenated with original CCFI bits to generate a longer sequence, allowing for efficient coding even when the total codeword length is not an integer multiple of three, and additional codebooks are generated through permutation to optimize resource mapping in fading channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If (3,2) codewords are used for CCFI channel coding, then coding efficiency is improved for integer multiple cases, but adaptability deteriorates when total coded length is not an integer multiple of three
Solution Approach 1:
The CCFI bits are divided into two segments: those that form complete (3,2) codewords and those that remain as uncoded bits. This segmentation allows the system to efficiently code the majority of bits using the (3,2) codeword structure while accommodating the remaining bits that result from non-integer multiple divisions, thereby resolving the contradiction between coding efficiency and adaptability.
Solution Approach 2:
The coding method is designed to handle both integer multiple cases (using repeated (3,2) codewords) and non-integer multiple cases (using a combination of repeated codewords and uncoded bits). This multi-functionality allows the same coding mechanism to adapt to different CCFI lengths without requiring separate handling for each case, thus improving both efficiency and adaptability.
2Reliability
If repeated (3,2) codewords are used, then error correction is improved for integer multiple cases, but device complexity increases when total length is not an integer multiple of three
Solution Approach 1:
The coding process segments the CCFI bits into codable portions (forming complete (3,2) codewords) and uncoded portions (remaining bits). This segmentation simplifies the overall mechanism by allowing the system to use the well-established (3,2) codeword repetition for error correction on the codable portions while simply transmitting the uncoded portions as-is, avoiding the need for complex handling of all possible non-integer multiple scenarios.
Solution Approach 2:
Instead of attempting to code all CCFI bits when the length is not an integer multiple of three, the method applies partial coding to only those bits that can form complete (3,2) codewords. This partial action approach maintains error correction capability for the codable portions while avoiding the complexity of forcing a complete coding solution for non-integer multiple cases.
3Productivity
If CCFI bits are mapped to resource units, then resource utilization is improved, but measurement precision of channel conditions deteriorates in fading environments
Solution Approach 1:
The patent applies different coding strategies to different portions of the CCFI bits based on their local characteristics. Complete (3,2) codewords receive repetition coding for enhanced reliability, while remaining uncoded bits are transmitted as-is. This local differentiation allows optimal resource utilization for each portion while maintaining the ability to detect channel conditions through the transmitted signal structure.
Solution Approach 2:
The receiver uses the structure of transmitted CCFI signals (both coded and uncoded portions) to feedback about channel conditions. The presence and reception of repeated (3,2) codewords provide information about channel quality, enabling the system to adapt to fading conditions while maintaining efficient resource utilization through the mapping of CCFI bits to resource units.
Data Source
AI summary
A method of transmitting a control channel format indicator (CCFI), also known as PCFICH (Physical Control Format Indicator Channel), in case where the length of a coded CCFI is not an integer multiple of three, including mapping a plurality of two-bit CCFI into a codebook with each component codeword having three bits; generating a sequence of codewords selected from the codebook by repeating the selected component codeword for predetermined times; generating a codeword by concatenating the sequence of the selected component codewords with the original CCFI bits; and transmitting the codeword carrying information of CCFI. The method further includes a step of generating a permutation of each of the four codewords by assigning K repetitions of the three-bit component codeword to the number of K resource units respectively and mapping remaining K bits of each of the four codewords separately to the number of K resource units.