Discrete multitone based wireline telemetry system for single-mode telemetry applications

1 . A method performed by a surface acquisition module in a discrete multitone modulation (DMT) system, the method comprising:

initiating a first training sequence with a downhole telemetry module using a first bandwidth of a plurality of bandwidths via a communication link between the surface acquisition module and the downhole telemetry module;

receiving, during the first training sequence, a set of training tones from the downhole telemetry module via the communication link;

measuring a respective power of a first training tone of the set of training tones and a second training tone of the set of training tones;

automatically selecting a second bandwidth of the plurality of bandwidths for a communication session between the surface acquisition module and the downhole telemetry module using the communication link, based on the first training sequence, the second bandwidth being greater than the first bandwidth, and the second bandwidth being automatically selected when the power of the first training tone and the power of the second training tone satisfy a predetermined condition; and

exchanging data with the downhole telemetry module during the communication session based on the second bandwidth.

2 . The method of claim 1 , wherein the predetermined condition comprises a difference between the power of the first training tone and the power of the second training tone being greater than a threshold.

3 . The method of claim 1 , further comprising initiating a second training sequence with the downhole telemetry module at the second bandwidth, after initiating the first training sequence and prior to exchanging data with the downhole telemetry module during the communication session.

4 . The method of claim 3 , further comprising:

determining, during the second training sequence, one or more metrics indicative of a quality of the communication link;

determining a usable portion of the second bandwidth for the communication link, based on the one or more metrics;

allocating available transmission power to the usable portion of the second bandwidth; and

initiating a third training sequence with the downhole telemetry module, based on the transmission power allocated to the usable portion of the second bandwidth, after initiating the second training sequence and prior to exchanging data with the downhole telemetry module during the communication session.

5 . The method of claim 4 , wherein:

the second bandwidth comprises a plurality of subcarriers;

the usable portion of the second bandwidth comprises a first set of subcarriers of the plurality of subcarriers; and

allocating the available transmission power to the usable portion of the second bandwidth comprises reallocating transmission power from a second set of subcarriers of the plurality of subcarriers to the first set of subcarriers.

6 . The method of claim 4 , wherein the one or more metrics comprise a signal-to-noise ratio (SNR) of the communication link.

7 . The method of claim 4 , further comprising adjusting, during the third training sequence, a receiver gain of the surface acquisition module based at least in part on the transmission power allocated to the usable portion of the second bandwidth.

8 . The method of claim 1 , wherein exchanging data with the downhole telemetry module comprises:

receiving, from the downhole telemetry module, an indication of a bit allocation table (BAT) update; and

dynamically allocating data among a set of subcarriers within the second bandwidth, based on the BAT update.

9 . The method of claim 8 , wherein the BAT update is based on a respective signal-to-noise ratio (SNR) of each subcarrier of the set of subcarriers.

10 . The method of claim 9 , wherein dynamically allocating the data among the set of subcarriers comprises moving a number of bits from a first subcarrier within the set of subcarriers to a second subcarrier within the set of subcarriers.

11 . The method of claim 10 , wherein the first subcarrier has an SNR margin less than an SNR margin of the second subcarrier.

12 . The method of claim 8 , further comprising receiving a bit-swapping request from the downhole telemetry module during the communication session, wherein dynamically allocating the data among the set of subcarriers comprises:

dynamically allocating the data among the set of subcarriers in response to the bit-swapping request; and

refraining from sending an acknowledgment to the downhole telemetry module after dynamically allocating the data among the set of subcarriers.

13 . The method of claim 12 , wherein the bit-swapping request is included within an acknowledgment message.

14 . The method of claim 1 , wherein:

exchanging data with the downhole telemetry module comprises transmitting data to the downhole telemetry module using an error control coding scheme; and

using the error control coding scheme comprises:

performing a first set of operations of the error control coding scheme via a first processor; and

offloading a second set of operations of the error control coding scheme to a second processor.

15 . The method of claim 14 , wherein the error control coding scheme comprises trellis coded modulation.

16 . A surface acquisition module for a discrete multitone modulation (DMT) system, the surface acquisition module comprising:

one or more memories collectively storing instructions; and

one or more processors communicatively coupled to the one or more memories, the one or more processors being collectively configured to execute the instructions to cause the surface acquisition module to:

initiate a first training sequence with a downhole telemetry module at a first bandwidth of a plurality of bandwidths via a communication link between the surface acquisition module and the downhole telemetry module;

receive, during the first training sequence, a set of training tones from the downhole telemetry module via the communication link;

measure a respective power of a first training tone of the set of training tones and a second training tone of the set of training tones;

automatically select a second bandwidth of the plurality of bandwidths for a communication session between the surface acquisition module and the downhole telemetry module using the communication link, based on the first training sequence, the second bandwidth being greater than the first bandwidth, and the second bandwidth being automatically selected when the power of the first training tone and the power of the second training tone satisfy a predetermined condition; and

exchange data with the downhole telemetry module during the communication session according to the second bandwidth.

17 . The surface acquisition module of claim 16 , wherein the predetermined condition comprises a difference between the power of the first training tone and the power of the second training tone being greater than a threshold.

18 . The surface acquisition module of claim 16 , wherein the one or more processors are collectively further configured to execute the instructions to cause the surface acquisition module to initiate a second training sequence with the downhole telemetry module at the second bandwidth, after initiating the first training sequence and prior to exchanging data with the downhole telemetry module during the communication session.

19 . The surface acquisition module of claim 18 , wherein the one or more processors are collectively further configured to execute the instructions to cause the surface acquisition module to:

determine, during the second training sequence, one or more metrics indicative of a quality of the communication link;

determine a usable portion of the second bandwidth for the communication link, based on the one or more metrics;

allocate available transmission power to the usable portion of the second bandwidth; and

initiate a third training sequence with the downhole telemetry module, based on the transmission power allocated to the usable portion of the second bandwidth, after initiating the second training sequence and prior to exchanging data with the downhole telemetry module during the communication session.

20 . The surface acquisition module of claim 19 , wherein:

the second bandwidth comprises a plurality of subcarriers;

the usable portion of the second bandwidth comprises a first set of subcarriers of the plurality of subcarriers; and

allocating the available transmission power to the usable portion of the second bandwidth comprises reallocating transmission power from a second set of subcarriers of the plurality of subcarriers to the first set of subcarriers.