Superposition Coding for Wireless Air Link Resource Efficiency
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Solution Overview
Problem
Wireless communications systems face inefficiencies in using air link resources for downlink traffic channel signaling due to varying user data needs, leading to wasted resources and interference, particularly when high and low data rate users share the same air link resources.
Innovation Solution
Implementing superposition coding techniques in base stations, where different sets of data are transmitted using the same communication segment with varying power levels for non-zero modulation symbols, allowing for efficient use of air link resources and minimizing interference by combining modulation symbol streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If superposition signaling is implemented to increase the number of active users, then user capacity is improved, but interference problems occur
Solution Approach 1:
The patent applies local quality by assigning different power levels to different users within the same air link resource. High data rate users receive signals at higher power levels while low data rate users receive signals at lower power levels, allowing both to coexist on the same resource without excessive interference. This differential power assignment resolves the contradiction between increasing user capacity and controlling interference.
Solution Approach 2:
The patent changes the power level parameter for different users to enable superposition signaling. By adjusting the power levels of modulation symbols directed to different users, the system can support multiple users simultaneously on the same air link resource while managing interference through parameter optimization rather than resource allocation alone.
2Device complexity
If fixed number of MTUs are used for convenience of assignment, then assignment complexity is reduced, but air link resource efficiency deteriorates
Solution Approach 1:
The patent introduces dynamic resource allocation where the number of MTUs assigned to each user can vary based on their specific data requirements. Instead of fixed MTU allocations, the system dynamically adjusts the number of minimum transmission units assigned to high or low data rate users, improving air link resource efficiency while maintaining manageable assignment complexity through structured allocation rules.
Data Source
AI summary
A device includes a zero symbol rate (ZSR) coding/modulation module and a second type coding/modulation module. Both modules generate modulation symbols to be conveyed using the same air link resources but with the non-zero ZSR symbols having a higher power level. The ZSR module generates a mixture of zero and non-zero modulation symbols. A ZSR modulation scheme communicates information using both the position of the non-zero modulation symbols and the phase and/or amplitude of the non-zero modulation symbols. Different ZSR schemes, implementing different ratios relating the number of zero symbols to the total number of symbols, can be associated with different low data rates while second module modulation schemes can be associated with different high data rates. Modulation symbols from two modules are in some embodiments, superimposed. In some embodiments, non-zero ZSR modulation symbols punch out second module modulation symbols which occupy the same air link resource.