OFDMA Wireless Access Point Secondary Channel Allocation
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Solution Overview
Problem
In wireless LAN systems conforming to the IEEE 802.11 standard, the difference in channel bandwidths supported by wireless access points and stations leads to underutilization of frequency resources, resulting in degraded throughput and service quality as the number of low-function/capability stations increases.
Innovation Solution
The implementation of a wireless communication system and method that utilizes orthogonal frequency-division multiple access (OFDMA) to efficiently use secondary channels, allowing data to be transmitted simultaneously to stations that can handle OFDMA through unused secondary channels while maintaining transmission to legacy stations on primary channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the wireless access point uses a wide channel bandwidth (40 MHz, 80 MHz, or 160 MHz), then the transmission speed and frequency utilization are improved, but the compatibility with legacy wireless stations (IEEE 802.11a) that only support 20 MHz is degraded
Solution Approach 1:
The wide bandwidth channel is divided into multiple sub-channels (e.g., four 20 MHz sub-channels in an 80 MHz band). The access point assigns different sub-channels to different wireless stations based on their capabilities. Legacy stations receive data on dedicated 20 MHz sub-channels, while OFDMA-capable stations utilize multiple sub-channels simultaneously, thus resolving the contradiction between wide bandwidth utilization and legacy station compatibility.
Solution Approach 2:
The patent introduces a new dimension of resource allocation by implementing OFDMA (Orthogonal Frequency Division Multiple Access), which allows multiple users to access different frequency sub-carriers simultaneously within the same time slot. This transforms the single-dimensional channel allocation into a multi-dimensional frequency-resource allocation scheme, enabling both legacy and advanced stations to coexist efficiently in the wide bandwidth environment.
2Productivity
If the channel bandwidth is extended to increase throughput, then the frequency resource utilization is improved, but the system complexity increases due to the need to support multiple bandwidth configurations
Solution Approach 1:
The access point is designed with multi-functionality to support multiple bandwidth configurations (20 MHz, 40 MHz, 80 MHz, 160 MHz) and multiple access modes (legacy OFDM and OFDMA). The system dynamically selects and switches between different bandwidth and access modes based on the capabilities of connected wireless stations, thereby achieving universal compatibility while maintaining high throughput without excessive complexity.
3Productivity
If data is transmitted sequentially to multiple wireless stations on the same channel, then the system maintains simplicity, but the frequency resource utilization and throughput are degraded
Solution Approach 1:
The patent merges multiple communication streams into a single OFDMA transmission framework. Instead of sequentially transmitting to multiple stations on the same channel, the access point combines frequency resources and simultaneously transmits data to multiple wireless stations (both legacy and OFDMA-capable) within the same time slot using different sub-carriers. This merging approach significantly improves frequency resource utilization while maintaining manageable protocol complexity through unified resource allocation mechanisms.
Data Source
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AI summary
In order to provide a wireless communication system capable of improving the throughput of wireless communication by effectively using frequency resources, in a wireless communication system in which a first wireless access point which communicates with one or more wireless stations within a first cell by orthogonal frequency-division multiple access and a second wireless access point which is capable of performing carrier sensing with the first wireless access point and communicates with one or more wireless stations within a second cell by the orthogonal frequency-division multiple access operate in cooperation with each other, the first wireless access point includes an access right acquiring means which acquires an access right when data to be transmitted is generated; and a transmitting means of permission for use which transmits permission for use of channels which are not scheduled to use within the first cell, to the second wireless access point in a period in which the access right is acquired, and the second wireless access point includes a communication means which communicates with the wireless station within the second cell via the channel in which the permission for use is acquired.