Robust telemetry repeater network system and method
A robust network telemetry repeater system exploits the repeater structure of data propagation and transmission and reception bi-directionality to increase network robustness. For example, multiple perceived receive attempts are created with no additional overhead. The system can be configured whereby nodes “hear” the transmissions of both adjacent and non-adjacent nodes forming implicit acknowledgement (“Acks”), and originating nodes can retransmit until implicit acknowledgments (“Acks”) are “heard,” indicating a successful link relay. Implicit acknowledgment can be applied to bidirectional networks, and bidirectional action can enable all nodes in the network to know the status of all other nodes.
1. A wireless acoustic telemetry repeater network system for a well including a wellbore structure extending subsurface downwardly from the Earth's surface, which telemetry network system includes:
multiple network nodes associated with and distributed along said structure;
said network nodes adapted for receiving and transmitting telemetry signals bidirectionally;
a first node receiving a transmission signal from a second node;
said first node using said received transmission signal to measure a physical communication transmission medium channel between said first and second nodes;
said channel measure comprised of one or more of the following: the transmission medium frequency response and time responses, received signal power as a function of frequency and time, noise power as a function of frequency and time;
said system using said channel measures to optimize usage of the physical communication transmission medium channel and one or more of the following: link robustness, node battery power consumption and link data rate;
said first node comprising a signal originating node and said second node comprising a signal destination node, said destination node configured for relaying back to the originating node to measure the transmission medium frequency response at the originating node; and
said system using channel measures to optimize link robustness, battery power consumption and transmission data rate by altering at least one of: transmit power; transmission baud rate; signal modulation type and modulation configuration; error correction scheme or parameters of an error correction scheme; transmission frequency; transmission medium; transmit power allocation over frequency and time, modulation or error correction as a function of frequency and time; and signal modulated data content; and
said system using said channel measures to alter an Orthogonal Frequency Division Multiplexing (OFDM) signal modulation configuration.
2. The telemetry network system according to claim 1 wherein said OFDM configuration includes: subcarrier transmit power level, subcarrier frequency assignments, subcarrier modulation type, subcarrier data loading, error correction coding, symbol duration, symbol cyclic prefix duration, and symbol transmission power.