MoCA Coaxial Node TEQ Filtering for Shorter Cyclic Prefixes
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Solution Overview
Problem
Coaxial networks, such as those operating according to the Multimedia over Coax Alliance (MoCA) standards, face reduced throughput due to the bandwidth consumption of long cyclic prefixes used to address multipath issues in OFDM signals, necessitating the need for communication nodes and methods that utilize shorter cyclic prefixes to enhance throughput.
Innovation Solution
The implementation of a channel-shortening time-domain equalizer (TEQ) filter in communication nodes that determines the delay spread of the coaxial channel and instructs transmitting nodes to shorten the cyclic prefix, allowing for the use of reduced-length cyclic prefixes, thereby improving throughput by minimizing bandwidth consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If long cyclic prefixes are used to address multipath issues, then multipath mitigation is improved, but bandwidth consumption increases and throughput decreases
Solution Approach 1:
The patent changes the parameter of cyclic prefix length from a fixed long duration to a variable shorter duration. By dynamically adjusting the cyclic prefix length based on channel conditions and using TEQ filter coefficients to compensate for multipath effects, the system maintains reliable multipath mitigation while reducing the bandwidth consumed by cyclic prefixes, thereby improving overall throughput
Solution Approach 2:
The patent introduces a time-domain equalizer (TEQ) filter as an intermediary mechanism. The TEQ filter processes the received signal to compensate for channel distortions and multipath effects, allowing the system to use shorter cyclic prefixes while maintaining signal integrity and multipath mitigation performance
2Reliability
If long cyclic prefixes are used to cover delay spread, then channel coverage is improved, but bandwidth efficiency deteriorates
Solution Approach 1:
The patent modifies the cyclic prefix length parameter from a conservative long duration that covers maximum delay spread to a shorter adaptive duration. By combining shorter cyclic prefixes with TEQ filtering, the system maintains adequate channel coverage for multipath components while significantly improving bandwidth efficiency and reducing energy loss
3Productivity
If shorter cyclic prefixes are used to increase throughput, then bandwidth efficiency is improved, but multipath mitigation capability deteriorates
Solution Approach 1:
The patent employs the TEQ filter as a compensatory intermediary that processes signals with shorter cyclic prefixes. The filter uses calculated coefficients to equalize the channel response and suppress multipath interference, enabling the system to use shorter cyclic prefixes for improved throughput while maintaining multipath mitigation capability through active signal processing
Solution Approach 2:
The patent performs preliminary calculation of TEQ filter coefficients based on channel impulse response or training sequences before actual data transmission. This preliminary action prepares the equalizer to effectively compensate for multipath effects in subsequent communications, allowing shorter cyclic prefixes to be used with confidence that multipath mitigation will be maintained
Data Source
AI summary
A coaxial network communication node receives multimedia content with one or more other nodes in a Multimedia over Coax Alliance (MoCA®) coaxial network. The node determines a delay-spread of a coaxial channel based on a probe received from a transmitting node during a link-maintenance operation (LMO) cycle. The probe is stored and reused during the LMO until the channel-shortening TEQ filter converges. The node configures a channel-shortening time-domain equalizer (TEQ) filter to effectively shorten the channel and instructs the transmitting node to shorten a length of a cyclic prefix for subsequent packet-based transmissions.