High Speed Overlay Mode for 802.15.4 Burst Data
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Solution Overview
Problem
Current wireless communication systems, such as those using the IEEE 802.15.4 standard, face limitations in data transfer rates, particularly for burst data and real-time audio applications, due to the application of spreading code modulation across entire data packets, which reduces effective data throughput and is not sufficient for high-rate data transmission.
Innovation Solution
Implementing a high-speed overlay mode by selectively applying spreading code modulation only to the synchronization header structure of data frames, allowing the data payload to be transmitted without spreading, thereby increasing data throughput to up to 2 Mbps while maintaining synchronization benefits and minimizing hardware changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spreading code modulation is applied to entire data packets in 802.15.4 standard, then synchronization and robustness are improved, but data throughput is reduced to slightly greater than 100 kbps
Solution Approach 1:
The patent divides the data packet into two segments: the synchronization header structure (first portion) and the data payload (second portion). Spreading code modulation is selectively applied only to the synchronization header structure to maintain robustness and synchronization, while the data payload is transmitted without spreading to maximize throughput. This segmentation allows each portion to be optimized for its specific function.
Solution Approach 2:
The patent applies different modulation characteristics to different parts of the data packet. The synchronization header structure receives spreading code modulation to ensure reliable detection and synchronization, while the data payload uses non-spread modulation for higher speed. This local differentiation of quality ensures that each component receives the appropriate level of processing for its specific requirements.
2Productivity
If multiple channels are used to increase data rate, then throughput is improved, but device complexity and cost increase due to requirement for multiple transceivers
Solution Approach 1:
The patent implements a dynamic modulation strategy where the system can switch between standard 802.15.4 mode and high-speed overlay mode based on data type and requirements. In high-speed overlay mode, spreading is disabled for data payloads to achieve higher throughput (up to 2 Mbps) using a single transceiver, eliminating the need for multiple transceivers while maintaining the ability to operate in standard mode when needed.
3Reliability
If spreading code modulation is applied to data payload, then error resistance is improved, but data transfer speed is reduced
Solution Approach 1:
The patent segments the data packet such that only the synchronization header structure undergoes spreading code modulation for error resistance, while the data payload is transmitted without spreading to maximize speed. This segmentation allows the system to achieve both reliability in synchronization and high speed in data transfer simultaneously.
Solution Approach 2:
Instead of applying spreading to the entire packet (excessive action), the patent applies spreading only to the necessary portion (synchronization header) for achieving reliable synchronization. This partial action reduces the overhead and increases the effective data transfer rate while maintaining sufficient error resistance for the critical synchronization function.
Data Source
AI summary
In a wireless 802.15.4 communication system (300), a high-speed data frame structure (340) is provided which uses the 802.15.4 SHR structure that is spread modulated to obtain the synchronization benefits of the 802.15.4 protocol, but which uses a modified data frame structure for the payload portion without using spreading to thereby improve its transmission efficiency. The transmission efficiency can be further increased by increasing the size of the data payload (and correspondingly, the frame length size).