Wireless Transmitter Bit Mapping for Frequency Diversity Gain
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Solution Overview
Problem
Existing wireless communication systems, such as IEEE 802.11n, face challenges in maintaining decoding performance when contiguous bits of an encoding block have the same reliability on a signal constellation, particularly in supporting broader bandwidths without increasing the complexity of the interleaver size.
Innovation Solution
The method involves segment parsing, where bits of a codeword are allocated to different subblocks with varying reliabilities on the signal constellation, using a stream parser to divide the data into frequency subblocks and independently interleaving them, allowing for wider bandwidth support without enlarging the interleaver size, and employing space-time block coding and cyclic shift delay for transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the size of the interleaver is increased to support a larger frequency band, then coding gain and diversity gain are improved, but device complexity and burden on changing existing structure increase
Solution Approach 1:
The patent divides the encoded bits into multiple groups and applies different mapping patterns to different groups. Specifically, first encoded bits are mapped using a first mapping pattern while second encoded bits are mapped using a second mapping pattern, where the patterns differ in how they assign bits to constellation points. This segmentation allows the system to achieve diversity gain without requiring a larger interleaver structure.
Solution Approach 2:
The patent applies different mapping patterns to different portions of the encoded data stream. The first mapping pattern is applied to first encoded bits while the second mapping pattern is applied to second encoded bits. This local differentiation in mapping quality ensures that contiguous bits do not continuously have the same reliability, achieving diversity gain through localized variation rather than global interleaving.
2Ease of manufacture
If contiguous bits of an encoding block continuously have the same reliability on a signal constellation, then mapping is simplified, but decoding performance deteriorates
Solution Approach 1:
The patent introduces dynamic switching between different mapping patterns based on the position in the encoded bit stream. The transmitter determines whether to apply the first or second mapping pattern dynamically, and the receiver correspondsingly switches between first and second decoding patterns. This dynamic adaptation ensures that contiguous bits do not have the same reliability without requiring complex static interleaving structures.
Solution Approach 2:
The patent changes the mapping parameters between different groups of encoded bits. The first mapping pattern and second mapping pattern differ in their parameter configurations, such as which constellation points are assigned to which bit values. By changing these mapping parameters for different bit groups, the system ensures varying reliability for contiguous bits while maintaining relatively simple mapping operations.
Data Source
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AI summary
Provided are a transmitter and a method for transmitting a data block in a wireless communication system. The method comprises the following steps: deciding the number of bits (s) and encoders (NES) to allocate to one axis of a signal constellation; encoding an information bit based on the s and the NES and generating a coded block; parsing the coded block based on the s and the NES and generating a plurality of frequency sub-blocks; and transmitting the plurality of frequency sub-blocks to a receiver.