Uplink OTFDM Symbol Multiplexing for Low-Latency 5G Transmission
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Solution Overview
Problem
Current 5G standards face challenges with low power-amplifier efficiency and high latency due to the use of conventional OFDM waveforms that require separate symbols for data and reference signals, leading to increased latency and overhead, which is not suitable for future wireless communication systems requiring extremely low latency and high energy efficiency.
Innovation Solution
A new waveform technology using Orthogonal Time Frequency-Division Multiplexing (OTFDM) that time-multiplexes data, control, and reference signals within a single OFDM symbol, allowing for low PAPR, high PA efficiency, and low latency transmission through time division multiplexing, with flexible RS overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional OFDM waveform is used with separate symbols for data and reference signals, then frequency multiplexing is achieved, but latency increases and power amplifier efficiency decreases
Solution Approach 1:
The patent merges data and reference signals into a single OFDM symbol by time-multiplexing them in the time domain. This combining approach eliminates the need for separate symbols, reducing latency while maintaining channel estimation functionality through the integrated structure.
Solution Approach 2:
The patent transitions from frequency-domain multiplexing to time-domain multiplexing within a single symbol. By changing the dimension of signal separation from frequency to time, it achieves lower latency while preserving the ability to transmit both data and reference signals simultaneously in different time slots.
2Reliability
If separate OFDM symbols are used for reference signals and data, then reliable channel estimation is achieved, but RS overhead increases to 50%
Solution Approach 1:
The patent combines reference signals and data within a single OFDM symbol structure, time-multiplexing them. This merging reduces the overhead dedicated to reference signals while maintaining reliable channel estimation by ensuring reference signals are present in every transmitted symbol rather than requiring separate dedicated symbols.
Solution Approach 2:
The patent enables flexible allocation of time resources within the single symbol, allowing dynamic adjustment of reference signal positioning and duration based on channel conditions and traffic requirements, thereby optimizing the balance between channel estimation reliability and overhead reduction.
3Use of energy by moving object
If DFT-S-OFDM waveform is used with dedicated OFDM symbol for RS, then power amplifier efficiency is improved, but latency doubles compared to single symbol transmission
Solution Approach 1:
The patent merges reference signals and data into a single time-multiplexed structure within one OFDM symbol. This eliminates the need for multiple sequential symbols, reducing transmission latency while maintaining the low PAPR characteristics of DFT-S-OFDM that enable power amplifier efficiency.
Solution Approach 2:
The patent segments the single symbol into time-multiplexed portions for reference signals and data, allowing both to coexist in a compressed timeframe. This segmentation within a single symbol achieves the dual goal of low latency and efficient power amplifier operation.
Data Source
AI summary
Embodiments of the present disclosure relate methods for generating and transmitting uplink Orthogonal time frequency-division multiplexing (OTFDM) symbols and the transmitters thereof. The method comprising time-multiplexing by one or more transmitters, at least one of a physical uplink control channel (PUCCH) sequence, a Physical Uplink Shared Channel (PUSCH) sequence and a reference sequence (RS) to generate a multiplexed sequence. The multiplexed sequence is processed to generate one or more PUCCH-PUSCH OTFDM symbols. Also, a method of generating and transmitting one or more PUCCH-PUSCH OTFDM slots, one or more PRACH OTFDM symbols and an uplink frame id provided.