Communication Node Signal Power Modulation for Spatial Reuse
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Solution Overview
Problem
Existing communication network technologies, such as IEEE 802.11 wireless networks, face challenges in efficiently managing transmit power and data rate due to reliance on inaccurate propagation models and the need for explicit signaling, particularly when multiple nodes are sending data concurrently, which limits spatial reuse of the channel.
Innovation Solution
A method where nodes modulate signal power and data rate by alternating between two different power levels over specific time periods, implicitly conveying this information without explicit messages, allowing for dynamic power and data rate control based on the number of sender nodes and signal attenuation, enabling accurate identification of concurrent senders and optimal channel access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If explicit signaling messages are used to exchange power and data rate information between source and receiver nodes, then accurate power and data rate control can be achieved, but device complexity and signaling overhead increase
Solution Approach 1:
The patent extracts the power and data rate information from explicit signaling messages and embeds it directly into the physical layer signal transmission. The source node modulates the signal power to encode power level information, and the receiver node decodes this information without requiring separate signaling exchanges, thereby eliminating signaling overhead while maintaining control accuracy
Solution Approach 2:
The receiver node autonomously determines the transmit power and data rate by measuring the received signal power and comparing it with the carrier sense threshold. This self-determination mechanism eliminates the need for the receiver to send feedback messages about interference levels, making the system self-configuring and reducing signaling complexity
2Reliability
If the maximum power level is determined for the worst case assuming a single concurrent sender node, then interference to ongoing calls is avoided, but spatial reuse of the channel is reduced when multiple concurrent senders are present
Solution Approach 1:
The patent changes the parameter used for power control from a static worst-case assumption to a dynamic threshold-based measurement. The carrier sense threshold is adjusted based on the received signal power, allowing the system to adapt to actual channel conditions and the presence of multiple concurrent senders, thereby improving spatial reuse while maintaining reliable interference avoidance
Solution Approach 2:
The system transitions from a static power control mechanism (fixed maximum power for worst case) to a dynamic mechanism where the effective transmit power is determined by real-time signal measurements and threshold comparisons. This dynamic adaptation allows multiple nodes to concurrently transmit at appropriate power levels based on actual channel conditions, increasing spatial reuse
3Productivity
If transmit power is reduced to enable spatial reuse, then channel capacity increases, but the signal-to-interference ratio may fall below the threshold required for the chosen data rate
Solution Approach 1:
The patent changes the carrier sense threshold parameter dynamically based on the received signal power. When signal power is high, the threshold is raised, allowing lower transmit powers and better spatial reuse. When signal power is low, the threshold is lowered, ensuring sufficient signal-to-interference ratio for reliable communication. This parameter adaptation resolves the contradiction between spatial reuse and reliability
4Measurement precision
If the receiver node sends the measured interference level to the source node, then accurate power determination is possible, but information exchange overhead increases before data transmission
Solution Approach 1:
The patent extracts the interference level information from separate feedback messages and incorporates it directly into the physical layer signal characteristics. The receiver node's measured signal power becomes the basis for the carrier sense threshold, eliminating the need for explicit interference level reporting and reducing pre-transmission information exchange overhead
Data Source
AI summary
A transmission method is used by a node of a communications network, wherein nodes communicate with one another via a carrier-sense multiple-access channel, said method comprising a step of sending a signal at a given transmit power and a given data rate to a receiver node over the channel, and wherein the transmit power of the sent signal assumes successively a first power value during a first time period and then a second power value during a second time period, the two power values being different and one of them being equal to the given power, the first time period representing the given power and the second time period representing the data rate. The invention also relates to a method of receiving a signal sent by the transmission method enabling the transmit power and the data rate used by the sender node to be deduced from the received signal.