Guard Subcarrier Allocation for OFDM Interference
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Solution Overview
Problem
The conventional LTE system faces challenges in providing low latency communication and efficiently allocating frequency resources, especially when multiplexing legacy OFDM and next-generation waveforms like UF-OFDM, due to interference and non-ideal wireless channel characteristics.
Innovation Solution
A method for allocating frequency resources in a wireless communication system by differentiating guard subcarriers and subcarriers transmitting null data, where guard subcarriers do not transmit control or user data, and subcarriers transmitting null data only transmit control information, is proposed. This involves determining frequency resource sizes and allocating these subcarriers between legacy OFDM and UF-OFDM systems in a frequency domain, with the option to shift subcarriers and allocate null data to prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If legacy OFDM and UF-OFDM systems are multiplexed in frequency domain, then frequency resource utilization is improved, but interference between systems increases
Solution Approach 1:
The patent introduces guard subcarriers as intermediary elements between legacy OFDM and UF-OFDM systems in the frequency domain. These guard subcarriers act as a buffer that prevents direct interference between the two systems while allowing both to coexist and utilize frequency resources efficiently. The guard subcarriers are specifically designed not to transmit control or user data, thereby creating a protective zone that isolates the two waveform types.
2Object-affected harmful factors
If guard subcarriers are allocated between OFDM systems, then interference is minimized, but frequency resource efficiency decreases
Solution Approach 1:
The patent applies local quality by differentiating the functions of different subcarriers in specific locations. Guard subcarriers are allocated only at specific boundaries where interference occurs, rather than throughout the entire frequency spectrum. This localized approach to interference protection minimizes the impact on overall frequency resource efficiency while still providing necessary isolation between legacy OFDM and UF-OFDM systems.
3Adaptability or versatility
If subcarrier allocation is flexible with shifting, then resource allocation adaptability is improved, but system complexity increases
Solution Approach 1:
The patent introduces dynamic subcarrier allocation mechanisms that allow flexible shifting of subcarriers between legacy OFDM and UF-OFDM systems. This dynamic approach enables the system to adapt to different traffic conditions, channel characteristics, and interference scenarios by adjusting subcarrier positions in real-time. The flexibility is implemented through configurable parameters that control the shifting behavior, balancing adaptability with manageable complexity.
Data Source
AI summary
Provided are a method and an apparatus for allocating, by a first OFDM system and a second OFDM system, frequency resources, which are multiplexed in a frequency region, in a wireless communication system. Specifically, the sizes of the frequency resources of the first OFDM system, which corresponds to an existing OFDM, and the second OFDM system, which corresponds to a UF-OFDM, are determined. Adjacent subcarriers are instructed to allocate any one of a guard carrier and a subcarrier to which null data is allocated, while performing frequency resource allocation between the first and second OFDM systems in accordance with the determined sizes of the frequency resources. The information regarding the frequency resource allocation, which comprises information indicative of either the guard carrier or the subcarrier, is transmitted.