DFT-S-OFDMA Resource Allocation via Message-Passing Segmentation
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Solution Overview
Problem
DFT-S-OFDMA systems face challenges in balancing peak-to-average-power ratio (PAPR) and scheduling gain, particularly for cell edge users, where localized subcarrier mapping reduces PAPR but limits throughput, and existing resource allocation methods fail to maximize weighted sum rate effectively in multi-cell scenarios.
Innovation Solution
The system employs message-passing based resource allocation algorithms that split users into sub-users with identical rewards, allowing multiple frequency chunks assignment, and uses polynomial-time processes to optimize chunk allocation across cells, considering practical modulation and coding schemes, and interference from adjacent cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If localized subcarrier mapping is used in DFT-S-OFDMA, then PAPR is reduced, but throughput and scheduling gain are limited
Solution Approach 1:
The system segments users into sub-users and allocates multiple non-contiguous frequency chunks to each user. This segmentation allows the system to achieve frequency diversity gain (improving throughput) while maintaining localized mapping benefits (controlling PAPR) for each individual chunk.
Solution Approach 2:
The patent transitions from single contiguous frequency allocation to multi-dimensional frequency chunk allocation. Users can be assigned multiple discrete frequency chunks across the spectrum, adding a new dimension to resource allocation that simultaneously achieves frequency diversity and PAPR control.
2Productivity
If multiple frequency chunks are assigned to a user, then data rate is increased, but PAPR increases
Solution Approach 1:
Each frequency chunk assigned to a user maintains localized mapping properties, ensuring that within each chunk the signal characteristics remain favorable for PAPR control. The overall user signal is composed of multiple such locally-optimized chunks, achieving both high data rate and acceptable PAPR.
Solution Approach 2:
The system dynamically adjusts the number and distribution of frequency chunks assigned to each user based on channel conditions, user location (cell edge vs. cell interior), and QoS requirements. This dynamic allocation allows flexible trade-off between data rate and PAPR for different users and conditions.
3Productivity
If frequency dependent scheduling gain is maximized, then throughput improves, but PAPR increases
Solution Approach 1:
The scheduling gain is achieved through segmented frequency chunk allocation rather than single large contiguous allocation. Each chunk can be independently optimized for frequency-dependent scheduling while maintaining localized mapping, thus achieving both scheduling gain and PAPR control.
Data Source
AI summary
Systems and methods are disclosed to allocate resources in discrete Fourier transform spread orthogonal frequency division multiple access (DFT-S-OFDMA) networks, which involve determining a reward for each user when assigned a frequency chunk (FC) of subcarriers, where each FC is a set of contiguous subcarriers; splitting each user into one or more sub-users, with each sub-user having identical rewards; and assigning resources with a message-passing based FC allocation.