Polar-Coded Beam Sweeping Broadcast for Adjacent-Block LLR Combining
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Solution Overview
Problem
In 5G wireless communication systems, particularly in beam sweeping scenarios, receivers face challenges in combining signals from adjacent beams due to block-dependent time indices, which prevents direct addition of log-likelihood ratios (LLRs) from adjacent blocks, leading to suboptimal signal reception.
Innovation Solution
The implementation of superposition coding using polar codes, where a time-varying component (time index) is encoded and superimposed on the non-time-varying component (system information), allowing for removal of the time-varying component at the receiver to accumulate and decode the non-time-varying component from multiple blocks, and using a second channel code to facilitate direct decoding of combined LLRs without hypothesizing the time index.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If beam sweeping is used to broadcast system information in multiple directions, then coverage area is improved, but signal combination at receiver becomes complex due to block-dependent time indices
Solution Approach 1:
The patent segments the encoded bits into two distinct parts: a common part (system information) and a specific part (time index). This segmentation allows the receiver to separately process these components, enabling signal combination from multiple beams while maintaining the ability to identify and handle time-varying information. The common part can be accumulated across blocks while the specific part carries block-specific timing information.
Solution Approach 2:
The patent extracts the time index information from the system information block and encodes it separately as a specific part. This extraction allows the receiver to remove or handle the time-varying component independently when combining signals from multiple beams, reducing the complexity of signal combination while preserving coverage benefits.
2Measurement precision
If time index is included in each beam's system information, then receiver can determine radio frame boundaries, but direct addition of LLRs from adjacent blocks is prevented
Solution Approach 1:
The patent divides the transmitted information into a common part (system information without time index) and a specific part (time index). This segmentation enables the receiver to extract precise timing information for radio frame boundary detection while simultaneously allowing the common part to be combined across multiple blocks through simple LLR addition, as it contains no block-specific variations.
Solution Approach 2:
The time index is extracted and encoded separately in the specific part of the transmission. The receiver can then use this extracted time index to accurately determine radio frame boundaries while ignoring or separately handling this component during the signal combination process, enabling straightforward LLR addition for the common part.
3Reliability
If polar codes are used for encoding, then capacity-achieving performance is achieved, but decoding latency increases due to need to hypothesize time index
Solution Approach 1:
The patent segments the polar code encoding into two parts: common information encoded in one set of bits and time index encoded in another set. This segmentation allows the receiver to decode the common part independently without needing to hypothesize about the time index, significantly reducing decoding latency while maintaining the reliability benefits of polar codes for both parts.
Data Source
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AI summary
According to some embodiments, a method in a wireless transmitter comprises: obtaining a first set of bits (comprising a non-time-varying component) for wireless transmission; concatenating a second set of bits (comprising a time-varying component (e.g., beam identifier)) to the first set of bits; encoding the concatenated first and second set of bits using a channel code; and transmitting the encoded bits to a wireless receiver. In some embodiments, transmitting the encoded bits to the wireless receiver comprises transmitting a first beam. The method may further comprise: concatenating a third set of bits (comprising a time-varying component (e.g., beam identifier)) to the first set of wireless bits; encoding the concatenated first and third set of bits using a channel code; and transmitting the encoded bits to a wireless receiver using a second beam.