Localized Distributed Resource Allocation in OFDMA Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In orthogonal frequency division multiple access (OFDMA) communication systems, particularly in UMTS LTE, existing methods struggle to efficiently allocate resources for both localized and distributed transmissions without causing clashes, especially when dealing with fast-moving user equipment, as they require complex signaling to manage tones allocated randomly across the bandwidth.
Innovation Solution
A method that sets specific time and frequency chunks for localized and distributed resources within a band, allowing coexistence by signaling resource allocation within the same frequency range, enabling users to recognize their allocations without explicit notification, and subdividing chunks to accommodate varying bandwidth requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If distributed transmission allocates tones randomly across the whole bandwidth, then frequency diversity is improved, but resource allocation complexity and signaling overhead increase due to potential clashes with localized transmissions
Solution Approach 1:
The patent segments the frequency spectrum into distinct localized and distributed resource regions. Distributed transmissions are allocated specific frequency regions rather than random tones across the entire bandwidth, while localized transmissions occupy other regions. This segmentation eliminates tone clashes between transmission types and reduces signaling complexity while maintaining frequency diversity benefits for distributed users.
2Reliability
If signaling is used to notify localized terminals of tones already in use by distributed transmissions, then resource collision is prevented, but signaling overhead increases
Solution Approach 1:
The patent extracts the resource allocation notification function from explicit signaling by implementing implicit resource allocation. Each transmission type (localized and distributed) is assigned specific frequency regions, and terminals independently determine their allocated tones based on their transmission type and the predefined region assignments. This eliminates the need for signaling to notify terminals of tones already in use, reducing signaling overhead while preventing resource collisions.
3Productivity
If localized resource blocks are allocated at frequencies with good radio channel quality, then transmission efficiency is improved, but this approach fails for fast-moving user equipment and group transmissions
Solution Approach 1:
The patent implements dynamic resource allocation where the system can adapt between localized and distributed transmission modes based on user equipment mobility characteristics. For fast-moving users or group transmissions, the system switches to distributed transmission with allocated frequency regions that provide frequency diversity. For stationary or slow-moving users, localized transmission with frequency-selective resource allocation optimizes transmission efficiency. This dynamic adaptation resolves the contradiction between transmission efficiency and adaptability to different mobility patterns.
Data Source
AI summary
Resources are allocated in a communication system by setting specific time and frequency chunks within a band to provide localized and distributed resources for each of localized and distributed users. The signalling of resource allocation for each user is in the chunk at the same frequency range as the frequency range of the allocated resource, or a subset of the frequency range of the allocated resource.