Gateway Link Management for Disjoint CDMA Subnets
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Solution Overview
Problem
In mobile ad-hoc networks, joining disjoint subnets is challenging due to interference and latency issues caused by increasing power or reducing data rates, which affects network performance and efficiency.
Innovation Solution
The method involves gateway nodes communicating to determine achievable rates between them, allowing subnets to join only if the rates meet a threshold, and then reducing signal transmit rates to a predetermined level, thereby managing power and rate changes to minimize interference and maintain network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If nodes increase transmit power to extend network range and join new subnets, then network coverage is improved, but CDMA interference increases
Solution Approach 1:
The patent dynamically adjusts transmit power and data rate parameters based on channel conditions and subnet distance. Nodes transition between different power levels (e.g., from normal operating power to elevated discovery power) and data rates (e.g., from high-rate traffic channel to lower-rate probe channel) to optimize both coverage extension and interference management during subnet joining operations
Solution Approach 2:
The patent implements periodic probe channel transmissions at scheduled intervals for subnet discovery and gateway selection. Instead of continuous high-power transmission, nodes periodically activate probe channels to detect and evaluate external subnets, thereby extending coverage while limiting interference to specific time windows when discovery is needed
2Area of stationary object
If nodes reduce data rate to extend communication range for subnet joining, then network coverage is improved, but network latency increases
Solution Approach 1:
The patent segments the communication process into distinct phases: probe channel discovery phase (using lower data rates for extended range) and traffic channel data transmission phase (using higher data rates for speed). By separating these functions into different channels and time periods, the system achieves extended coverage during discovery while maintaining low latency during actual data transfer
Solution Approach 2:
The patent uses periodic probe channel transmissions at optimized intervals to balance discovery needs with latency requirements. The periodic nature allows nodes to use lower data rates only when necessary for subnet discovery, while maintaining higher data rates for normal traffic, thereby extending range without permanently increasing network latency
3Adaptability or versatility
If many nodes transmit at high power to communicate between distant subnets, then subnet connectivity is improved, but network interference increases
Solution Approach 1:
The patent extracts the subnet discovery and gateway selection function from the normal traffic channel and places it on a dedicated probe channel. This separation allows high-power transmissions to be confined to the probe channel only when needed for subnet joining, while the traffic channel maintains normal power levels, thereby improving subnet connectivity without causing excessive interference to ongoing data transmissions
Solution Approach 2:
The patent introduces gateway nodes as intermediaries between distant subnets. Instead of requiring all nodes to transmit at high power for inter-subnet communication, only gateway nodes perform high-power probe channel transmissions to establish connections between subnets. This intermediary approach improves subnet connectivity while limiting high-power interference to specific gateway nodes rather than all nodes
Data Source
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AI summary
Joining subnets in mobile ad-hoc network (MANET) environment. A method includes, based on SNR, power and data rate information between a first gateway node for a first subnet and a second gateway node for a second subnet, determining a rate at which the first and the second subnets can connect if nodes in the first subnet reduce signal transmit rate to a predetermined level. The method further includes as a result of determining that the determined rate meets or exceeds a predetermined threshold, then joining the first and second subnets by joining the first and second subnets via the first and second gateway nodes and causing nodes in the first subnet to reduce signal transmit rate to the predetermined level.