Multiplexing Sequence-Based ACK/NACK for New Radio Uplink Control
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Solution Overview
Problem
Current sequence-based ACK/NACK techniques in new radio (NR) wireless communication systems are inefficient when transmitting acknowledgments (ACKs) or negative acknowledgments (NACKs) from multiple user equipment (UEs) to a base station, particularly in scenarios where multiple UEs share the same orthogonal frequency division multiplexing (OFDM) symbol.
Innovation Solution
The method involves determining the distance between UEs based on sequence length, number of hypotheses, or the number of UEs sharing an OFDM symbol, and assigning cyclic shifts and sequences to each UE to multiplex ACK/NACK bits in uplink control information (UCI) signals, allowing for efficient transmission via orthogonal frequency division multiplexing (OFDM) symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sequence based ACK/NACK technique is used for transmitting ACK/NACK bits in uplink short burst, then transmission efficiency is improved, but the technique does not work well when ACK/NACKs of multiple UEs are to be transmitted to base station
Solution Approach 1:
The patent segments the uplink short burst transmission by assigning different cyclic shifts of the same base sequence to different UEs. This segmentation allows multiple UEs to transmit simultaneously on the same time-frequency resources while maintaining distinguishability through orthogonal cyclic shifts, thereby resolving the contradiction between transmission efficiency and multi-UE reliability
Solution Approach 2:
The patent changes the cyclic shift parameter of the sequence to differentiate between multiple UEs. By varying the cyclic shift parameter while keeping the base sequence the same, the system enables multiple UEs to transmit ACK/NACK bits simultaneously without interference, maintaining both transmission efficiency and reliability
2Productivity
If multiple UEs share the same OFDM symbol for ACK/NACK transmission, then resource utilization is improved, but errors and dropped bits increase in the transmission
Solution Approach 1:
The patent applies preliminary action by pre-calculating and assigning orthogonal cyclic shifts to each UE before the actual ACK/NACK transmission. This preliminary assignment ensures that even when multiple UEs share the same OFDM symbol, their transmissions remain orthogonal and error-free, thus maintaining both resource utilization and transmission accuracy
Solution Approach 2:
The cyclic shift acts as an intermediary that enables multiple UEs to share the same OFDM symbol without causing errors. By introducing this intermediary parameter, the system transforms potentially conflicting transmissions into orthogonal signals, achieving both high resource utilization and transmission reliability
Data Source
AI summary
A method and apparatus for improved transmission of ACK and NACK bits to a base station The example method may determine a distance between a first UE and a second UE based on one or more of a sequence length, a number of hypothesis, or a number of UEs sharing an OFDM symbol. The example method may determine a plurality of cyclic shifts for each of the first UE and the second UE. The example method may assign one or more sequences to each UE. The example method may receive, at the base station, a multiplexed signal, wherein the multiplexed signal includes at least one bit of uplink control information (UCI) from the first UE and the second UE multiplexed on an uplink short burst transmitted via the OFDM symbol. The method may enable the receipt of UCI from multiple UEs in a multiplexed signal.