OFDMA Multi-RU Aggregation for Higher Spectrum Utilization
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Solution Overview
Problem
Current wireless communication protocols, such as IEEE 802.11ax, are inefficient as they often waste resource units (RUs) due to restrictions on orthogonal frequency division multiple access (OFDMA), especially when the number of users is small or when secondary channels are not available, leading to reduced spectrum efficiency.
Innovation Solution
An electronic device transmits OFDMA frames using multiple predefined RUs with varying tone numbers, allowing for efficient aggregation and error coding, interleaving, and symbol mapping across these RUs to enhance spectrum efficiency, even when secondary channels are not available.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If each station is assigned to one resource unit (RU) in OFDMA, then the system is simple to manage and allocate resources, but the spectrum efficiency deteriorates when the number of users is small or secondary channels are unavailable
Solution Approach 1:
The patent merges multiple RUs into a single aggregated RU that can be assigned to one station. This allows the station to utilize multiple frequency sub-channels (e.g., multiple 20 MHz channels) as if they were a single continuous resource, thereby improving spectrum efficiency without complicating the resource allocation mechanism from the network's perspective.
Solution Approach 2:
The patent introduces a new dimension of resource aggregation by combining RUs across different frequency sub-channels that were traditionally treated as separate dimensions. This allows stations to access resources in a multi-dimensional frequency space, effectively utilizing available spectrum even when some sub-channels are blocked or unavailable.
2Reliability
If the bandwidth is reduced to 20 MHz when secondary channels are unavailable, then the system maintains reliability by avoiding interference, but the spectrum efficiency deteriorates significantly
Solution Approach 1:
The patent segments the available spectrum into multiple frequency sub-channels and allows the station to aggregate only those sub-channels that are available and reliable. This segmentation approach enables selective utilization of clean frequency bands while excluding channels affected by interference or DFS active states, thereby maintaining reliability while maximizing usable bandwidth.
Solution Approach 2:
The patent implements dynamic RU aggregation where the aggregated RU configuration can change based on real-time channel conditions. When secondary channels become unavailable, the aggregation dynamically adjusts to include only available sub-channels, maintaining optimal spectrum efficiency under varying reliability conditions rather than statically reducing to 20 MHz.
3Productivity
If multiple RUs are allocated to a single station, then the spectrum efficiency improves by reducing waste, but the device complexity increases due to error coding, interleaving, and symbol mapping across multiple RUs
Solution Approach 1:
The patent merges multiple RUs into a unified aggregated RU structure, allowing error coding, interleaving, and symbol mapping to be performed on the aggregated structure as a whole rather than independently on each RU. This merging approach reduces the overall processing complexity compared to handling multiple separate RUs, while still achieving the spectrum efficiency benefits of multi-RU allocation.
4Productivity
If the center 26 tone RU is used in a 20 MHz channel assigned to two OFDMA users, then the resource utilization is maximized, but the spectrum efficiency deteriorates due to the wasted center RU
Solution Approach 1:
The patent extracts and removes the problematic center 26 tone RU from the traditional 20 MHz channel structure. By taking out this wasted resource element, the patent allows for more efficient packing and allocation of remaining frequency resources, eliminating the bandwidth waste that occurs when the center RU cannot be utilized by OFDMA users.
Data Source
AI summary
An electronic device (such as an access point) is described. This electronic device transmits an orthogonal frequency division multiple access (OFDMA) frame to a recipient electronic device (such as a client or a station). The OFDMA frame includes multiple predefined resource units (RUs) allocated to the recipient electronic device in a set of predefined RUs having associated frequency bandwidths. Moreover, the multiple predefined RUs include two or more first predefined RUs having a first number of tones less than a predefined amount, or two or more second predefined RUs having a second number of tones greater than or equal to the predefined amount. For example, the predefined amount may include 242 tones. Note that the multiple predefined RUs may have the same or different numbers of tones. Moreover, the electronic may receive an acknowledgment or a block acknowledgment from the recipient electronic device.