Accessory Device Communication via Host-Synchronized OFDMA
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Solution Overview
Problem
Existing systems face delays and interference when multiple accessory devices communicate with a host device, particularly due to time multiplexing, which can lead to systemic advantages or disadvantages for players in multiplayer scenarios and increased perceived input lag.
Innovation Solution
Implementing Orthogonal Frequency Division Multiple Access (OFDMA) to assign accessory devices a set of subcarriers with a bandwidth less than 20 MHz, synchronizing communication timing through a trigger signal, and using Dynamic Latency Input (DLI) to align data transmission with video frame timing, allowing simultaneous transmission of user inputs and state data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If time multiplexing is used to manage multiple accessory devices, then device complexity is reduced, but delays and interference occur leading to increased input lag
Solution Approach 1:
The patent segments the communication channel by assigning dedicated time slots and frequency resources to each accessory device. Instead of time multiplexing all devices sequentially, the system divides the available spectrum into multiple orthogonal frequency division multiple access (OFDMA) resource units, allowing simultaneous transmission from multiple devices without interference. This segmentation eliminates the delays inherent in time multiplexing while maintaining manageable system complexity through structured resource allocation.
Solution Approach 2:
The patent transitions from one-dimensional time multiplexing to two-dimensional resource allocation by introducing frequency as an additional dimension. Multiple accessory devices can transmit simultaneously on different frequency subcarriers within the same time slot, effectively moving from sequential time-based access to parallel frequency-based access. This dimensional change allows multiple devices to coexist without the temporal delays and interference problems of traditional time multiplexing.
2Speed
If multiple accessory devices communicate simultaneously, then user interaction responsiveness is improved, but interference and delays occur
Solution Approach 1:
The patent applies local quality by assigning specific frequency subcarriers and resource units to individual accessory devices based on their needs. Each device receives a customized allocation of spectral resources tailored to its data transmission requirements, allowing simultaneous operation with optimized local characteristics. This localized resource assignment enables multiple devices to transmit at high speeds without mutual interference, as each device operates on its designated frequency resources.
Solution Approach 2:
The patent implements preliminary action by pre-allocating frequency resources and time slots to accessory devices before communication occurs. The host device establishes resource assignments in advance, creating a structured framework that prevents interference before it can occur. This proactive resource management allows multiple devices to transmit simultaneously at high speeds without the conflicts and delays that would arise from ad-hoc access attempts.
3Productivity
If bandwidth is increased for accessory devices, then data transmission capability is improved, but resource allocation complexity increases
Solution Approach 1:
The patent segments the total available bandwidth into multiple smaller orthogonal frequency division multiplexing (OFDM) subcarriers that can be systematically allocated to different accessory devices. This segmentation transforms the complex task of allocating large bandwidth chunks into a manageable process of assigning specific subcarrier groups and resource units. The structured segmentation enables efficient high-speed data transmission while keeping resource allocation complexity tractable through standardized allocation patterns.
Data Source
AI summary
A host device includes a processor, a wireless communication device in data communication with the processor, and a hardware storage device in data communication with the processor. The hardware storage device has instructions stored thereon that, when executed by the processor, cause the host device to establish a wireless data channel with an accessory device and assign the wireless data channel to a resource unit with a bandwidth less than 20 MHz. The instructions further cause the host device to send a trigger signal to the accessory device and receive state data from the accessory device in response to the trigger signal.