Precoder for Repeated Modulation Symbols in Wireless Communications
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communications systems face challenges in efficiently supporting a wide range of devices with varying data traffic profiles and low power consumption requirements, particularly in 5G and IoT applications, where devices have different latency and reliability needs.
Innovation Solution
A communications device configured to apply a precoder to repeated modulation symbols, allowing for single subcarrier transmission by concentrating energy in a selected subcarrier, enabling efficient power management and spectral efficiency improvements through modulation symbol repetition and precoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple subcarriers are used for transmission, then data rate is improved, but power spectral density decreases and power consumption increases
Solution Approach 1:
The transmission is segmented into multiple slots, each carrying a repeated copy of the same modulation symbol. This segmentation allows the system to achieve diversity gain while maintaining concentrated power spectral density on selected subcarriers, thereby reducing overall power consumption while supporting data transmission
Solution Approach 2:
Instead of uniformly distributing power across all subcarriers, the system applies precoding to concentrate power on specific selected subcarriers. This local quality approach ensures high power spectral density on chosen subcarriers while leaving other subcarriers with zero or reduced power, thus improving energy efficiency
2Use of energy by moving object
If power is concentrated on selected subcarriers, then power spectral density is improved, but device complexity increases due to precoding operations
Solution Approach 1:
The system changes the parameter of power distribution by applying precoding weights to concentrate power on selected subcarriers. This parameter change achieves high power spectral density while the precoding operation, though adding some complexity, is computationally efficient and can be pre-calculated
Solution Approach 2:
The precoding operation is performed in advance on the modulation symbols before transmission. This preliminary action prepares the signal with the desired power distribution pattern, simplifying the real-time transmission process and reducing operational complexity during actual data transfer
3Productivity
If modulation symbol repetition is applied, then spectral efficiency is improved, but transmission time increases
Solution Approach 1:
The system uses periodic repetition of modulation symbols across multiple slots, where each repetition carries the same information. This periodic action provides frequency diversity and improves spectral efficiency through better signal detection, while the repetitions are scheduled efficiently to minimize overall transmission time
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A communications device for use in a wireless communications system comprising an infrastructure equipment and the communications device is provided. The communications device is configured to transmit an uplink channel to the infrastructure equipment in a plurality of allocated subcarriers. The communications device comprises circuitry for one or more modulation symbol repetition blocks, each configured to receive modulated symbols mapped to one of a plurality of modulated symbol sets and to repeat each of the received modulated symbols within each of the plurality of modulated symbol sets, and circuitry for a precoder block configured to carry out a precoder function on the repeated modulation symbols, the precoder function comprising multiplying each of the repeated modulation symbols by an element of a precoder vector to produce precoded symbols.