Dynamic Multiplexing Switching for Wireless Systems
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Solution Overview
Problem
Wireless communication systems face challenges in balancing flexibility and power efficiency, particularly in multipath environments and high SNR scenarios, where existing technologies like CDMA and OFDM struggle with channel reuse, interference, and high Peak to Average Power Ratio (PAPR).
Innovation Solution
A system that dynamically or semi-statically switches between multi-carrier and single-carrier multiplexing schemes based on user equipment (UE) SNR, using OFDM for high SNR scenarios and LFDM for low SNR scenarios, allowing for flexible resource allocation and reduced PAPR through DFT transformation and pilot sequence generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If OFDM is used for broadband data transmission, then spectral efficiency and multipath handling are improved, but PAPR increases leading to lower power efficiency
Solution Approach 1:
The system dynamically selects between OFDM and SC-FDM multiplexing schemes based on channel conditions, data rate requirements, and power efficiency considerations. The base station can switch between schemes for different users or different time periods, allowing the system to adapt to varying operational requirements and optimize both spectral efficiency and power efficiency in different scenarios.
Solution Approach 2:
The patent changes the fundamental parameter of multiplexing scheme (from single-carrier to multi-carrier and vice versa) to resolve the contradiction. By adjusting this high-level system parameter based on operational conditions, the system can achieve high spectral efficiency when using OFDM or maintain good power efficiency when using SC-FDM, thus resolving the trade-off between these two competing objectives.
2Adaptability or versatility
If CDMA allows channel reuse among adjacent cells, then system flexibility is improved, but interference at cell boundaries increases and capacity decreases
Solution Approach 1:
The system segments the frequency spectrum into multiple orthogonal sub-carriers and assigns different sets of sub-carriers to different users and different cells. This frequency-domain segmentation, combined with orthogonal resource allocation, allows channel reuse in adjacent cells while maintaining orthogonality and eliminating interference, thus resolving the contradiction between channel reuse flexibility and interference control.
3Use of energy by moving object
If SC-FDM is used to reduce PAPR, then power efficiency is improved, but scheduling flexibility is restricted
Solution Approach 1:
The base station dynamically determines whether to use SC-FDM or OFDM for each user equipment based on current operational conditions. When power efficiency is the primary concern, SC-FDM is selected; when scheduling flexibility is more important, OFDM is used. This dynamic selection allows the system to optimize for the appropriate objective based on real-time requirements.
Solution Approach 2:
The system implements a universal multiplexing framework that can operate in both SC-FDM and OFDM modes, making the communication system multi-functional. This allows the same system infrastructure to serve both power-efficient operations (via SC-FDM) and flexible scheduling operations (via OFDM), depending on which function is needed at any given time.
Data Source
AI summary
A communication system that facilitates transmissions in accordance with a single-carrier (SC) multiplexing scheme, a multi carrier (MC) multiplexing scheme or a combination thereof is disclosed. Based on various factors such as attributes associated with a UE (user equipment) or availability of resources, a base station can signal to the UE an appropriate multiplexing scheme to be adopted for particular transmissions. The UE can be scheduled for transmission in a semi-static mode wherein the UE employs the transmission scheme for a particular time interval or it may change the mode dynamically for different transmissions. For transmissions from the UE comprising a plurality of data streams with dissimilar attributes, the base station implements a MIMO (multiple input multiple output) system for the UE. This facilitates a UE to dynamically switch between or simultaneously adopt the various multiplexing schemes for communications and thereby fully utilize advantages associated with the different schemes.