Baseband Processor HARQ-ACK Joint Encoding for Uplink Control
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Solution Overview
Problem
In wireless communication systems, especially with LTE-Advanced, the uplink HARQ-ACK feedback mechanism faces challenges with increased downlink carrier aggregation, leading to unnecessary UCI overhead and intra-cell interference due to incorrect detection of downlink control channels, resulting in reduced reliability and spectral efficiency.
Innovation Solution
A baseband processor that generates a CRC code word based on HARQ-ACK feedback bits and jointly encodes radio network parameters with the CRC, ensuring accurate arrangement and number of HARQ-ACK bits, thereby reducing overhead and improving reliability by avoiding encoding SR bits with HARQ-ACK bits and using CRC for error detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of aggregated downlink carriers is increased to expand bandwidth and increase data rate, then downlink throughput is improved, but uplink control information overhead increases and reliability deteriorates
Solution Approach 1:
The patent extracts and removes unnecessary HARQ-ACK feedback bits corresponding to unscheduled carriers from the uplink control information. The base station selectively feeds back only HARQ-ACK bits for carriers where data was actually scheduled, eliminating redundant feedback for carriers without data transmission and thereby reducing uplink overhead while maintaining reliability.
Solution Approach 2:
The patent implements dynamic adaptation of the number of HARQ-ACK feedback bits based on actual scheduling decisions. The base station determines the number of feedback bits dynamically according to which carriers were scheduled for data transmission, allowing the uplink control information to adapt its size to actual system state rather than using a fixed maximum size.
2Productivity
If dynamic signaling is used to indicate the number of HARQ-ACK bits to reduce overhead, then spectral efficiency is improved, but decoding reliability deteriorates due to potential signaling errors
Solution Approach 1:
The patent applies beforehand cushioning by using CRC (Cyclic Redundancy Check) codes to protect the dynamic signaling information about the number of HARQ-ACK bits. The CRC code provides error detection and correction capability for the signaling bits, ensuring that if signaling errors occur, the base station can detect and correct them, thereby maintaining decoding reliability while still benefiting from dynamic overhead reduction.
Data Source
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AI summary
The present invention relates to a baseband processor (600), comprising a receiver circuit configured to receive a downlink carrier aggregation transmission, wherein the baseband processor (600) further comprises an encoder (102) configured to generate a Cyclic Redundancy Check, CRC, code word based on at least one Hybrid Automatic Repeat Request - Acknowledgment, HARQ-ACK, feedback bit in response to the downlink carrier aggregation transmission, jointly encode at least one radio network parameter (P) of a user device (100) with the CRC code word, and generate an uplink control information message (M) comprising the at least one HARQ-ACK feedback bit and the jointly encoded radio network parameter and CRC code word. The present invention also relates to a baseband processor (700), comprising: a receiver circuit (304) configured to receive an uplink control information message (M) in an uplink channel, the uplink control information message (M) comprising at least one HARQ-ACK feedback bit in response to a downlink carrier aggregation transmission and at least one jointly encoded radio network parameter and CRC code word for a user device (100), wherein the CRC code word is based on the at least one HARQ-ACK feedback bit; and a decoder (302) configured to decode the received uplink control information message (M) and output the at least one HARQ-ACK feedback bit and the radio network parameter (P) if a correct CRC condition is met. Furthermore, the present invention also relates to corresponding methods, a wireless communication system, a computer program, and a computer program product.