CA2906905C

CA2906905C - Network telemetry system and method

Info

Publication number: CA2906905C
Application number: CA2906905A
Authority: CA
Inventors: John-Peter Van Zelm
Original assignee: Baker Hughes Oilfield Operations LLC
Current assignee: Baker Hughes Oilfield Operations LLC
Priority date: 2013-03-15
Filing date: 2014-03-17
Publication date: 2023-03-28
Anticipated expiration: 2034-03-17
Also published as: EP2972527B1; WO2014145848A3; CA2906905A1; EP2972527A4; WO2014145848A2; EP2972527A2; WO2014145848A4; US20140266769A1; BR112015023566A2

Abstract

A telemetry system produces, transmits and receives signal sets from network nodes, which correspond to transceiver stations. Repeater scheduling and other interference mitigating techniques are utilized to simultaneously transmit from multiple nodes with minimized network degradation. Update interval/rate and network throughput are thereby fixed regardless of the number of network nodes and a network telemetry method is provided using the system.

Description

NETWORK TELEMETRY SYSTEM AND METHOD

BACKGROUND OF THE INVENTION
1. Field of the Invention

[0002] The present invention relates generally to telemetry apparatuses and methods, and more particularly to acoustic telemetry increased throughput network systems and methods for the well construction (drilling, completion) and production (e.g., oil and gas) industries.
2. Description of the Related Art

[0003] Acoustic telemetry is a method of communication used in the well drilling, completion and production industries. In a typical drilling environment, acoustic extensional carrier waves from an acoustic telemetry device are modulated in order to carry information via the drillpipe as the transmission medium to the surface. Upon arrival at the surface, the waves are detected, decoded and displayed in order that drillers, geologists and others helping steer or control the well are provided with drilling and formation data. In production wells, downhole information can similarly be transmitted via the well casings.

[0004] The theory of acoustic telemetry as applied to communication along drillstrings has generally been confirmed by empirical data in the form of accurate measurements. It is now generally recognized that the nearly regular periodic structure of drillpipe imposes a passband/stopband structure on the frequency response, similar to that of a comb filter.
Dispersion, phase non-linearity and frequency-dependent attenuation make drillpipe a challenging medium for telemetry, the situation being made even more challenging by the significant surface and downhole noise generally experienced.

[0005] Drillstring acoustic telemetry systems are commonly designed with multiple transceiver nodes located at spaced intervals along the drillstring or wellbore. The nodes can be configured as signal repeaters as necessary. Acoustic telemetry networks can function in a synchronized fashion with the operation of the nodes and repeater nodes and other system components. Data packets consisting of downhole sensor data were relayed node to node, in a daisy chain or linear fashion, typically beginning from a node located in the borehole apparatus (BHA), through the network to a destination, usually the surface receiver system.
For purposes of minimizing interference between nodes, the data packets were transmitted (typically up-string) using time division multiplexing (TDM) techniques.
Maximizing data packet transmission speed and throughput are objectives of drillstring telemetry systems and methods. For a discussion of a repeater network for these applications, see U.S. Patent No.
9,458,711.

[0006] When exploring for oil or gas, and in other drilling applications, an acoustic transmitter can be placed near the BHA, typically near the drill bit where the transmitter can gather certain drilling, wellbore, and geological formation data, process this data, and then convert the data into a signal to be transmitted uphole to an appropriate receiving and decoding station. In some systems, the transmitter is designed to produce elastic extensional stress waves that propagate through the drillstring to the surface, where the waves are detected by sensors, such as accelerometers, attached to the drillstring or associated drilling rig equipment. These waves carry information of value to the drillers and others who are responsible for steering the well. Examples of such systems and their components are shown in: Drumheller U.S. Patent No. 5,128,901 for Acoustic Data Transmission through a Drillstring; Drumheller U.S. Patent No. 6,791,470 for Reducing Injection Loss in Drillstrings; Camwell et al. U.S. Patent No. 7,928,861 for Telemetry Wave Detection Apparatus and Method; and Camwell et al. U.S. Patent No. 8,115,651 for Drill String Telemetry Methods and Apparatus.
SUMMARY OF THE INVENTION
[00071 In the practice of the present invention, a network is configured with multiple nodes using the acoustic transmission channel simultaneously, i.e., "multiplexing" the channel. Network throughput is thus decoupled from the number of nodes and performance increases accordingly. Intemode interference can be controlled by one or more methods, including the following:
= Node transmission timing: nodes transmitting at separate times. Current (prior art) method which tends to be relatively inefficient. E.g., time division multiplexing (TDM).
= Attenuation where nodes transmit at the same time and interference is suppressed by differences in propagation distance and associated path loss (signal attenuation).
= Frequency differentiation where nodes transmit simultaneously on different frequencies whereby interference is suppressed by the frequency separations and associated filtering.
= Signal orthogonality with nodes transmitting at the same time but interference being suppressed by the orthogonal relationship of the signal sets.
= Directional transmitter and receiver configurations, with nodes tuned to transmit in the direction of the desired destination node or receive in the direction of the originating node, thereby minimizing interference within the network.
[007a] In a broad aspect, the present invention provides a linear wireless telemetry 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 wellbore structure; a sensor associated with one or more of said nodes and adapted for providing output comprising signal data corresponding to an operating or status condition; a transmitter associated with each of said nodes for propagating said signal data between nodes; a receiver associated with each of said nodes for receiving signals from other nodes; a node receiving a telemetry signal from another transmitting node forming an inter-node network link; said network being adapted for 3a simultaneous operation of multiple inter-node network links; and said multiple inter-node network links being located at different points along the network.
[007b] In another broad aspect, the present invention provides a linear wireless 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 nodes receiving a telemetry signal from first nodes and re-transmitting said telemetry signal to second nodes to effect relay links; said relay links daisy-chaining across multiple nodes forming a telemetry relay network; and said network being adapted for multiple telemetry signals traversing the network at different points simultaneously, so as to effect multiple concurrent relays within the network, thereby increasing network data throughput.
[007e1 In another broad aspect, the present invention provides a linear 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; each node including a transmitter and a receiver; each node simultaneously transmitting and receiving within a medium and a frequency range susceptible to signal interference; said nodes receiving a telemetry signal from a first node and re-transmitting said telemetry signal to a second node to effect a relay; said relay daisy-chaining across multiple nodes forming a telemetry relay network; said network being adapted for multiple nodes transmitting simultaneously so as to effect multiple concurrent relays within the network, thereby increasing network data throughput; an update interval and network throughput being independent of the number of network nodes; an estimation function including:
(a) a transmitter-to-receiver intra-node channel providing an output; (b) a filter adapted to an approximation of the channel between the respective node's transmitter and receiver; (c) said filter being adaptive and having the signal destined for transmission as a reference input; (d) a summer receiving outputs from said receiver channel and said adaptive filter; (e) said summer providing an error signal as a feedback output to said adaptive filter;
(f) said adaptive filter being adjusted so as to minimize error signal; and a receiver signal isolation function including: (a) an estimated intra-node transmitter-to-receiver channel filter having the signal destined for transmission as an input from the transmitter and providing an output 3b that is the estimated transmitter signal as perceived by the receiver; (b) a summer receiving inputs from said adaptive filter and the receiver signal output that are synchronized in time;
and (c) said summer providing an output comprising the received signal with reduced transmitter signal content.
[0008] Other objects and advantages of the present invention will be apparent from the following description. Detailed descriptions of exemplary embodiments are provided in the following sections. However, the invention is not limited to such embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. I is a diagram of a typical drilling rig, which can include an acoustic telemetry system with a downhole serial network embodying an aspect of the present invention.
[0010] FIG. 2 is a fragmentary, side-elevational and cross-sectional view of a typical is drillstring, which can provide the medium for acoustic telemetry transmissions for the present invention.

[00111 FIG. 3 is a schematic diagram of a prior art linear network timing control system with nodes transmitting sequentially at different times, following a time division multiplexing (TDM) approach [00121 FIG. 4 is a schematic diagram of a path loss attenuation isolation system with a two-node gap transmission schedule.
[00131 FIG. 5 is a schematic diagram of a path toss attenuation isolation system with a one-node gap transmission schedule.
[00141 FIG. 6 is a schematic diagram of a path loss attenuation isolation system wherein nodes transmit and receive simultaneously.
1.0 [00151 FIG. 7 is a schematic diagram of a configuration whereby a node is adapting a filter to estimate the channel between the node's transmitter and receiver.
100161 FIG. 8 is a schematic diagram showing receiver signal isolation from the transmitter signal.
[00171 FIG. 9 is a schematic diagram of an increased-rate linear telemetry network scheduling system using orthogonal signal sets.
[00181 FIG. 10 is a schematic diagram of another increased rate linear telemetry network scheduling system using orthogonal signal sets combined with simultaneous transmission and reception.
[00191 FIG. 11 is a schematic diagram showing an example of multi-node transmission in an along-string measurement (ASM) configuration with varying/accumulating node payloads.
100201 FIG. 12 is a schematic diagram illustrating a node receiving a portion of a desired signal transmission during an interference-free period.
[00211 FIG. 13 is a schematic diagram showing a system using directional transceivers to suppress intra-node interference and increase network throughput.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[00221 In the following description, reference is made to "up" and "down"
waves, but this is merely for convenience and clarity. It is to be understood that the present invention is not to be limited in this manner to conceptually simple applications in acoustic communication from the downhole end of the drillstring to the surface.
I. Drilling Rig, Drillstring and Well Environment [0023] Referring to the drawings in more detail, the reference numeral 2 generally designates a high throughput network system embodying an aspect of the present invention.
Without limitation on the generality of useful applications of the system 2, an exemplary application is in a drilling rig 4 (FIG. 1). For example, the rig 4 can include a derrick 6 suspending a traveling block 8 mounting a kelly swivel 10, which receives drilling mud via a kelly hose 11 for pumping downhole into a drillstring 12. The drillstring 12 is rotated by a kelly spinner 14 connected to a kelly pipe 16, which in turn connects to multiple drill pipe sections 18, which are interconnected by tool joints 19, thus forming a drillstring of considerable length, e.g., several kilometers, which can be guided downwardly and/or laterally using well-known techniques.
[0024] The drillstring 12 can terminate at or near a bottom-hole (borehole) apparatus (1311A) 20, which can be at or near an acoustic transceiver node (Primary) Station 0 (STO). Other rig configurations can likewise employ the present invention, including top-drive, coiled tubing, etc.
FIG. I also shows the components of the drillstring 12 just above the BHA 20, which can include, without limitation, a repeater transceiver node 26 (ST1) and an additional repeater transceiver node 22 (ST2). An upper, adjacent drillpipe section 18a is connected to the repeater 22 and the transmitter 26. A downhole adjacent drillpipe section 18b is connected to the transmitter 26 and the BHA 20. A surface receiver node 21 is located at the top of the drillstring 12 and is adapted for receiving the acoustic telemetry signals from the system 2 for further processing, e.g., by a processor or other output device for data analysis, recording, monitoring, displaying and other functions associated with a drilling operation.
[0025] FIG. 2 shows the internal construction of the drillstring 12, e.g., an inner drillpipe 30 within an outer casing 32. Interfaces 28a, 28b are provided for connecting drillpipe sections to each other and to the other drillpipe components, as described above. W.1 illustrates an acoustic, electromagnetic or other energy waveform transmitted along the drillstring 12, either upwardly, downwardly, or laterally (in the case of horizontal wells). The drillstring 12 can include multiple additional repeater transceiver nodes 22 at intervals determined by operating parameters such as optimizing signal transmission and reception with minimal delays and errors.
The drillstring 12 can also include multiple sensors along its length for producing output signals corresponding to various downhole conditions.

[0026j Data packets contain sensor or node status data and are transmitted from the primary node (e.g., STO, typically the deepest node) and relayed from node-to-node in a daisy-chain (herein interchangeably referred to also as linear or serial) fashion to the surface receiver (Surface Rx) 21, which is generally located at or near the wellhead. The data packets include sensor measurements from the BHA 20 and other sensors along the drillstring 12. Such data packet sensor measurements can include, without limitation, wellbore conditions (e.g., annular/bore/differential pressure, fluid flow, vibration, rotation, etc.).
Local sensor data can be added to the data packet being relayed at each sensor node, thus providing along-string-measurements (ASMs).
[00271 A single node functions as the master node (e.g., STO) and is typically an edge node at the top or bottom of the drillstring 12. The master node monitors well conditions and sends data packets of varying type and intervals accordingly.
II. Prior Art Acoustic Repeater Scheduling [00281 FIG. 3 shows the operation of a prior art linear telemetry network scheduling configuration where node transmissions are scheduled for separate non-overlapping time windows in order to prevent inter-node interference and the associated degradation in link performance (reliability and range). This constitutes time division multiplexing (TDM) channel management. However, the update interval increases with the number of nodes, whereby the network throughput decreases. For example, with a five-node, 20 bits per second (bps) transmission link rate system, neglecting guard and signal propagation times, the effective data rate (network throughput) is approximately (20 bps) / (5 nodes) = 4 bps, while in a 2 node network, the network throughput is approximately (20 bps)/ (2 nodes) = 10 bps.
III. Multiplexing Acoustic Transmission Channels [0029] Preferably multiple nodes are configured for using the acoustic transmission channels at the same time, i.e., "multiplexing" the drillstring channel. Multiplexing, with multiple nodes transmitting simultaneously, decouples network throughput dependency on the number of nodes, and increases performance. However, if not mitigated, multiple nodes transmitting simultaneously will lead to inter-node interference and an associated degradation in link performance. One or more of the following methods can be implemented to control intemode interference during multi-node transmission:

7 = Signal attenuation, with nodes transmitting simultaneously and interference being suppressed by differences in propagation distance and associated path loss, and perhaps further optimized through adjustment of node transmission power level.
= Frequency separation with nodes transmitting simultaneously but on different frequencies whereby interference is suppressed.
= Signal orthogonality, with nodes transmitting at the same time and interference being suppressed by low correlation between signals within allowable signal set.
= Directional transmitter and receiver configurations, with nodes tuned to transmit in the direction of the desired destination node or receive in the direction of the originating node, thereby minimizing interference within the network.
IV. Isolation Via Path Loss Attenuation [00301 FIG. 4 shows a 2-node gap multiplexing scheduling configuration.
Interfering transmissions are mitigated by physical separation (e.g., 2-node gap). This configuration is applicable to electromagnetic pulse systems as well as acoustic, and is further applicable to downlink, uplink and bi-directional networks. Interfering transmissions are mitigated by physical separation and associated signal propagation path loss: 3-link propagation path loss attenuation (desired) versus 1-link propagation path loss attenuation (interference). Additional interference minimization can be achieved through adjustment of the transmitter output power levels to minimize interference at one location, while providing sufficient signal power at the desired node receiver. Update interval/rate and network throughput are thus fixed regardless of the number of network nodes. Only latency increases with node number.
[00311 The interference between nodes can be further managed by coordinating network timing in such a manner that, while multiple node transmissions overlap in time, the desired signal precedes the anticipated interferer signal such that a sufficient portion of the desired signal experiences no interference allowing the receiving node to achieve more reliable signal detection, timing and phase recovery, and decoding once the interfering node begins transmission and signals overlap. This method allows the receiver to favour the desired signal over the interferer. See, e.g., FIG. 12, which is discussed below.
[00321 FIG. 5 shows a 1-node gap multiplexing scheduling configuration wherein multiple nodes are transmitting at the same time. This configuration is more aggressive than the 2-node

8 gap configuration shown in FIG. 4, having less interference suppression.
Interfering transmissions are mitigated by physical separation and associated path loss: 1-link path loss attenuation (desired) versus 2-link path loss attenuation (interference).
Update interval/rate and network throughput are thus fixed regardless of the number of network nodes.
Only latency increases with node number.
[0033] FIG. 6 shows scheduling with an update rate which can be fixed at approximately 2ttx, for example, regardless of the number of nodes. Only latency increases with node number.
The receiver must be able to operate during self-transmission, without being excessively degraded by self-interference. This can be accomplished by assigning non-interfering frequency or orthogonal signal sets to the transmitter and receiver. If the transmitter and a receiver operate in the same channel (time, frequency), or further interference suppression is desired, high-power interfering self-transmission signals can be isolated from received signals through channel estimation techniques, as described below.
[0034] FIG. 7 shows a "receive-while-transmitting" configuration wherein an estimating function with a feedback loop is used to estimate the in-node transmitter to receiver channel. A
transmitter (e.g., a piezo-electric stack, in the case of acoustics) to receiver (accelerometer, in the case of acoustics) channel estimation is shown, using an adaptive filter to emulate the intra-node channel. FIG. 8 shows how the estimated intra-node channel can be used to suppress self-interference. Specifically, by applying an estimated channel filter to the known transmitted signal (as derived in FIG. 7), to translate the signal to how the receiver would perceive it, and subtracting it from the composite receive signal (self-interference from transmitter + desired receive signal originating from another node) to provide output corresponding to the desired receive signal only.
[0035] FIG. 9 shows an increased rate repeater scheduling configuration assigning orthogonal (i.e., low-interference) signal sets (indicated by a, 0) to transmitter and receiver nodes, thereby allowing multiple signals in respective channels simultaneously, increasing the update rate and the effective data rate. The signal sets can be reused once interference nodes are sufficiently separated to ensure adequate interference isolation. The update interval, tvdare, is fixed at ¨24, regardless of the number of repeaters and only latency increases. The concept is the application of orthogonal multiple access techniques to increase channel efficiency (e.g., CDMA ¨ Code Domain Multiple Access, FDMA ¨ Frequency Domain Multiple Access, OFDM

9 ¨ Orthogonal Frequency Domain Multiplexing, etc.) as an alternative to the relatively inefficient TDM (Time Division Multiplexing) methods.
[0036] Examples of low-interference signal sets include: signals of non-overlapping frequencies (Frequency Division Multiplexing (FDM)), which can be contiguous frequency blocks (e.g., different passbands) or interleaved blocks (e.g., OFDM); signals of low cross-correlations, such as up/down, linear/exponential chirps, pseudorandom noise (PRN) sequences (Code Division Multiplexing (CDM)), e.g., Walsh codes, Hadamard, etc.; and signals transmitted on separate, isolated mediums (channels): acoustic, electromagnetic pulse, and mud pulse (MP); and propagation modes (e.g., axial, longitudinal and spiral).
[0037] FIG. 10 shows orthogonal signal sets combined with simultaneous transmit and receive, to providing an update rate, tõpdate, fixed at ¨t,õ regardless of the number of nodes whereby only latency increases with node number. Node receivers are able to operate during transmission with minimized intra-node (self) interference due to transmitter-receiver signal orthognality, as previously discussed. If the transmitter and the receiver operate in the same channel, high-power interfering self-transmission signals can be isolated from received signals through channel estimation techniques, as described below.
[0038] FIG. 11 is a schematic diagram showing an example of an along-string measurement (ASM) configuration with varying/accumulating node payloads and signal propagation interference isolation.
[0039] FIG. 12 shows signal transmission scheduling refinement whereby a desired transmission (e.g., from M2 Tx to M2 Rx) precedes an interfering transmission (e.g., from MI
Tx to M2 Rx), creating a short period of interference-free reception of the desired signal. This interference-free period improves signal detection, timing and phase recovery, effectively allowing the receiver (e.g., M2 Rx) to "lock" onto the desired signal, and generally improve link robustness.
[0040] FIG. 13 shows a system with directional transceivers for interference suppression.
The node receivers are tuned to receive upwardly-traveling signals and to suppress/reject downwardly-traveling signals. This can be accomplished by equipping an acoustic node with multiple transmitters and receivers, and phasing their outputs such that directional transmission or reception is achieved (e.g., transmissions propagate only uphole and receivers only detect signals originating from downhole, and vice-versa). The details of such an operation would be

10 known to one versed in antenna beam forming techniques, and as such will not be elaborated in this text. Receive and transmit directionality can be exploited together, or individually, to suppress interference between nodes, enabling multiple nodes to transmit at the same time.
Remaining interference is separated by a two-node gap.
[00411 The configurations described above have advantages of preserving multi-hop repeater network throughput, which is fundamentally related to channel multiplexing (reuse) efficiency.
Multiple nodes must share the channel, reducing system throughput proportionally to the number of nodes in a system. For example, a five-node system capable of 40 bits-per-second (bps) has a maximum throughput of only 40 bps / 5 nodes = 8 bps, neglecting guard and signal propagation times, while a two-node system has a maximum throughput of 40bps / 2 nodes =
20bps. All multi-hop linear telemetry systems will encounter the same limitation, including electromagnetic (EM) systems.
[00421 It is to be understood that the invention can be embodied and combined in various forms, and is not to be limited to the examples discussed above. The range of components and configurations which can be utilized in the practice of the present invention is virtually unlimited.

Claims

What is claimed is:

1. A linear wireless telemetry network system for a well including a wellbore structure extending subsurface downwardly from the Earth's surface, the telemetry network system comprising:
multiple network transceiver nodes associated with and distributed along said wellbore structure, said network transceiver nodes comprising a primary transceiver node, a surface transceiver node, and a plurality of repeater transceiver nodes interposed between said primary and surface receiver nodes at intervals selected to reduce transmission delays and errors, and each of said transceiver nodes comprising a transmitter, a receiver, and a filter for suppressing node self-interference during receive-while-transmitting operation of the transceiver node; and a sensor associated with one or more of said transceiver nodes and adapted for providing output comprising signal data corresponding to a downhole condition to the associated transceiver node for incorporation in a telemetry signal, wherein each repeater transceiver node is configured to receive a telemetry signal of a given single type from a downstream transceiver node to form an inter-node network link between said transceiver nodes, and wherein multiple inter-node network links between transceiver nodes at different points along the wellbore structure are formed simultaneously to allow multiple telemetry signals to traverse multiple repeater transceiver nodes at different locations along the wellbore structure simultaneously.

2. A linear wireless telemetry repeater network system for a well including a wellbore structure extending subsurface downwardly from the Earth's surface, the telemetry network system comprising:
multiple network transceiver nodes associated with and distributed along said wellbore structure, each of said transceiver nodes comprising a transmitter, a receiver, and a filter for suppressing node self-interference during receive-while-transmitting operation of the transceiver node, wherein each transceiver node is configured to receive a telemetry signal of a given single type from a downstream transceiver node and re-transmit said telemetry signal to an upstream transceiver node to effect a relay link between the transceiver nodes whereby relay links are effected across all of the transceiver nodes in a daisy-chain, and Date Recue/Date Received 2022-01-21 wherein multiple transceiver nodes are configured to receive a telemetry signal simultaneously to allow multiple telemetry signals to traverse multiple transceiver nodes at different points along the wellbore structure simultaneously, so as to effect multiple concurrent relay links.

3. The telemetry system according to claim 1 or 2, wherein the telemetry signals of the given single type are one of acoustic signals, electromagnetic (EM) signals, and fluid pressure waves.

4. The telemetry system according to any one of claims 1 to 3, wherein the filter of each transceiver node is adaptive and is configured to estimate an intra-node channel between the receiver and transmitter of the transceiver node and apply the intra-node channel estimation to the telemetry signal destined for transmission.

5. The telemetry system according to claim 2, further comprising:
a control system function coordinating timing whereby a desired telemetry signal precedes in time of an anticipated, overlapping interfering concurrent telemetry signal creating an interference-free time period at a transceiver node for reception of a portion of the desired signal, thereby allowing the receiver of the transceiver node to lock onto the desired telemetry signal and improve estimation of critical modulation parameters, and thereby improve the demodulation of remaining portions of the desired telemetry signal that may be subject to concurrent relay link interference.

6. The telemetry system according to claim 2 or 5 wherein the transceiver nodes are positioned at intervals along the wellbore structure to reduce transmission delays and errors.

7. A linear wireless acoustic telemetry repeater network system for a well including a wellbore structure extending subsurface downwardly from the Earth's surface, the telemetry network system comprising:
multiple network nodes associated with and distributed along said wellbore structure;
each node including a transmitter and a receiver;
Date Recue/Date Received 2022-01-21 each node simultaneously transmitting and receiving within a medium and a frequency range susceptible to signal interference;
each node receiving a telemetry signal of a given single type from a downstream node and re-transmitting said telemetry signal to an upstream node to effect a relay;
said relay daisy-chaining across multiple nodes thereby to form a telemetry relay network;
said relay network being adapted for multiple nodes transmitting simultaneously so as to effect multiple concurrent relays within the relay network, thereby increasing data throughput;
each node comprising an adaptive filter for suppressing node self-interference during receive-while-transmitting operation of the node, the adaptive filter comprising:
an estimation function including: (a) a transmitter-to-receiver intra-node channel providing an output; (b) an estimated channel filter adapted to an approximation of the channel between the transmitter and receiver of the node;
(c) said estimated channel filter having the signal destined for transmission as a reference input; (d) a summer receiving outputs from said intra-node channel and said estimated channel filter; (e) said summer providing an error signal as a feedback output to said estimated channel filter;
and (f) said estimated channel filter being adjusted so as to minimize error signal; and a receiver signal isolation function including: (a) an estimated intra-node transmitter-to-receiver channel filter having the signal destined for transmission as an input from the transmitter and providing an output that is the estimated transmitter signal as perceived by the receiver; (b) a summer receiving inputs from said estimated intra-node transmitter-to-receiver channel filter and the receiver signal output that are synchronized in time; and (c) said summer providing an output comprising the received signal with reduced transmitter signal content.

8. The telemetry system according to claim 7, further comprising:
a control system function coordinating network timing whereby a desired telemetry signal precedes in time of an anticipated, overlapping interfering concurrent telemetry signal creating an interference-free time period at a node for reception of a portion of the desired telemetry signal, thereby allowing the receiver of the node to lock onto the desired signal and improve estimation of critical modulation parameters, and thereby Date Recue/Date Received 2022-01-21 improve the demodulation of remaining portions of the desired telemetry signal that may be subject to concurrent relay interference.

9. The telemetry system according to claim 7 or 8, wherein:
interference between concurrent relays is managed through said nodes having predefined separations to ensure sufficient signal propagation associated attenuation so as to maintain interference at receivers within a tolerable range.

10. The telemetry system according to claim 7 or 8 wherein:
interference between concurrent relays is managed through said nodes controlling transmission power levels so as to maintain interference at receivers within a tolerable range.

11. The telemetry system according to any one of claims 8 to 10, wherein the telemetry signals of the given single type are one of acoustic signals, electromagnetic (EM) signals, and fluid pressure waves.
Date Recue/Date Received 2022-01-21