Simultaneous OFDMA and SCMA Signal Transmission
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Solution Overview
Problem
The computational capability of User Equipment (UEs) limits the number of signals that can be multiplexed and decoded in multi-user downlink transmission, restricting data rates in telecommunications systems.
Innovation Solution
Simultaneous transmission of Orthogonal Frequency Division Multiple Access (OFDMA) signals and code domain non-orthogonal multiplexed signals using Sparse Code Multiple Access (SCMA), with the option to map bits using Quadrature Amplitude Modulation (QAM) or Phase Shift Keying (PSK, and adjusting transmission power and multiplexing techniques based on decoding complexity and spectral efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If non-orthogonal multiplexing technique is used to increase the number of multiplexed signals, then spectral efficiency is improved, but decoding complexity increases beyond UE computational capability
Solution Approach 1:
The patent segments the set of available resource elements into multiple subsets and divides the multiplexed signals into different groups. Each group is assigned to a specific subset, allowing UEs to decode only the signals corresponding to their allocated subset. This segmentation reduces the decoding complexity for each UE while maintaining overall spectral efficiency through non-orthogonal multiplexing across the divided resources.
2Productivity
If more signals are multiplexed together to meet demand for higher data rates, then data rate is improved, but computational capability of UEs becomes insufficient
Solution Approach 1:
The patent introduces a new dimension of resource allocation by dividing resource elements into multiple subsets and assigning different groups of multiplexed signals to different subsets. This dimensional division allows the system to support more total multiplexed signals beyond what a single UE's computational capability could handle, as each UE only needs to process signals within its assigned subset rather than all multiplexed signals simultaneously.
3Ease of operation
If orthogonal multiplexing technique is used to reduce decoding complexity, then ease of operation is improved, but spectral efficiency decreases
Solution Approach 1:
The patent applies different multiplexing techniques to different local regions (subsets) of resource elements. Within each subset, orthogonal multiplexing is used to ensure simple decoding for UEs assigned to that subset. However, across different subsets, non-orthogonal multiplexing is employed to increase overall spectral efficiency. This local differentiation allows each UE to experience simple orthogonal decoding while the system achieves high spectral efficiency through non-orthogonal multiplexing in other regions.
Data Source
AI summary
Methods and apparatus as described herein for determining whether to transmit a signal to at least one receiver of a plurality of receivers with an orthogonal multiplexing technique while signals to a remainder of the plurality of receivers are simultaneously transmitted with a non-orthogonal multiplexing technique If it is determined that the signal should be transmitted to the at least one receiver with the orthogonal multiplexing technique, simultaneously transmitting the signal to the at least one receiver with the orthogonal multiplexing technique and the signals to the remainder of the plurality of receivers with the non-orthogonal multiplexing technique. Methods and apparatus are also described for decoding the signals on the receiving end.