US-12627412-B2 - Optimization of vehicle communications employing retransmission request protocol

US12627412B2US 12627412 B2US12627412 B2US 12627412B2US-12627412-B2

Abstract

A system of managing communications in a vehicle includes a telematics unit connected to the vehicle. The telematics unit is configured to execute a retransmission request protocol upon receipt of erroneous data. A command unit in communication with the telematics unit, the command unit having a processor and tangible, non-transitory memory on which instructions are recorded. The command unit is adapted to determine vehicle situational parameters at a beginning of a data communication cycle. The vehicle situational parameters including current location and navigation status of the vehicle. When a first retransmission according to the retransmission request protocol is detected, the vehicle situational parameters are updated. The command unit is adapted to determine a desirable value of a retransmission frequency for the retransmission request protocol based in part on the updated vehicle situational parameters. In one embodiment, the retransmission request protocol is Hybrid Automatic Repeat Request (HARQ).

Inventors

Venkata Naga Siva Vikas Vemuri
Andrew J Macdonald
Scott T. Droste

Assignees

GM Global Technology Operations LLC

Dates

Publication Date: 20260512
Application Date: 20221212

Claims (11)

1 . A system of managing communications in a vehicle, the system comprising: a command unit having a processor and tangible, non-transitory memory on which instructions are recorded, the command unit being adapted to: select an uplink session for the vehicle for execution of a transmission time interval (TTI) bundling protocol defined by a TTI number, the TTI bundling protocol being adapted to permit data transfer in multiple consecutive sub-frames with a single acknowledgement signal for an entire bundle; determine if the uplink session is a low-latency application having a latency below a predefined latency threshold; select the TTI number to be relatively small when the latency is below the predefined latency threshold and select the TTI number to be relatively large when the latency is at or above the predefined latency threshold; execute a retransmission request protocol upon receipt of erroneous data; determine vehicle situational parameters at a beginning of a data communication cycle, the vehicle situational parameters including current location and navigation status of the vehicle; when a first retransmission according to the retransmission request protocol is detected, determine updated values of the vehicle situational parameters; determine a desirable value for a retransmission frequency for the retransmission request protocol based in part on the updated values; determine if an average bit error rate for a group is greater than a predefined error rate threshold, the group having requirements for Enhanced Mobile Broadband applications and Ultra-Reliable Low Latency Communication (URLLC) applications, the vehicle being part of the group; estimate the requirements for the Enhanced Mobile Broadband applications and the Ultra-Reliable Low Latency Communication (URLLC) applications for the group when the average bit error rate is greater than the predefined error rate threshold; and reserve respective slots for the URLLC applications based on previous values of the retransmission frequency and a response time for the group.
2 . The system of claim 1 , wherein the retransmission request protocol is Hybrid Automatic Repeat Request (HARQ).
3 . The system of claim 1 , wherein the command unit is adapted to determine the desirable value for a response time based in part on the vehicle situational parameters, the response time being between receipt of the erroneous data and a response by the telematics unit.
4 . The system of claim 1 , wherein the vehicle situational parameters include respective locations and respective signal strengths of one or more cellular towers within a predefined radius of the vehicle.
5 . The system of claim 1 , wherein: the command unit is adapted to determine if an average data transfer rate required by a group of vehicles is above a predefined high threshold, the group having substantially similar downlink needs; and wherein the vehicle is part of the group.
6 . The system of claim 5 , wherein the command unit is adapted to: designate a lead vehicle in the group to estimate lost code-block-groups (CBGs) for the group when the average data transfer rate for the group is above the predefined high threshold, employ preemptive estimates for the retransmission frequency for the lost code-block-groups (CBGs) when the average data transfer rate for the group is below the predefined high threshold.
7 . The system of claim 1 , wherein the command unit is adapted to: maximize switching of the respective slots from the Enhanced Mobile Broadband applications to the URLLC applications when the average bit error rate is less than or equal to the predefined error rate threshold.
8 . A method of managing communications in a vehicle having a command unit having a processor and tangible, non-transitory memory on which instructions are recorded, the method comprising: selecting an uplink session for the vehicle for execution of a transmission time interval (TTI) bundling protocol defined by a TTI number, via the command unit, the TTI bundling protocol being adapted to permit data transfer in multiple consecutive sub-frames with a single acknowledgement signal for an entire bundle; determining if the uplink session is a low-latency application having a latency below a predefined latency threshold, via the command unit; selecting the TTI number to be relatively small when the latency is below the predefined latency threshold, via the command unit and selecting the TTI number to be relatively large when the latency is at or above the predefined latency threshold, via the command unit; executing a retransmission request protocol upon receipt of erroneous data, via the command unit; determining vehicle situational parameters at a beginning of a data communication cycle, via the command unit, the vehicle situational parameters including current location and navigation status of the vehicle; determining updated values of the vehicle situational parameters when a first retransmission according to the retransmission request protocol is detected, via the command unit; determining a desirable value of a retransmission frequency for the retransmission request protocol based in part on the updated values, via the command unit; determining if an average bit error rate for a group is greater than a predefined error rate threshold, the vehicle being part of the group, the group having requirements for both Enhanced Mobile Broadband applications and Ultra-Reliable Low Latency Communication (URLLC) applications, via the command unit; estimating the requirements for the Enhanced Mobile Broadband applications and the Ultra-Reliable Low Latency Communication (URLLC) applications for the group when the average bit error rate is greater than the predefined error rate threshold, via the command unit; reserving respective slots for the URLLC applications based on previous values of the retransmission frequency and a response time for the group, via the command unit; and maximizing switching of the respective slots from the Enhanced Mobile Broadband applications to the URLLC applications when the average bit error rate is less than or equal to the predefined error rate threshold, via the command unit.
9 . The method of claim 8 , further comprising: selecting the retransmission request protocol to be Hybrid Automatic Repeat Request (HARQ), via the command unit; and determining the desirable value for a response time based in part on the vehicle situational parameters, via the command unit, the response time being between receipt of the erroneous data and a response by the telematics unit.
10 . The method of claim 8 , further comprising: determining if an average data transfer rate required by a group of vehicles is above a predefined high threshold, via the command unit, the group having substantially similar downlink needs, the vehicle being part of the group.
11 . The method of claim 10 , further comprising: designating a lead vehicle in the group to estimate lost code-block-groups for the group when the data transfer rate requirement for the group is above the predefined high threshold, via the command unit; and employing preemptive estimates for the retransmission frequency of the lost code-block-groups when the data transfer rate requirement for the group is below the predefined high threshold, via the command unit.

Description

INTRODUCTION The present disclosure relates generally to a system and method for managing communications in a vehicle employing a retransmission request protocol. The ever-increasing complexity of devices has led to an increase in wireless communication between various entities. For example, a vehicle may utilize cellular communications while driving along a road surface. Various protocols have been developed to efficiently implement such communications. One such protocol is the Hybrid Automatic Repeat Request (HARQ), whereby a retransmission request is automatically submitted to a sender by a receiver when erroneous data is received. The retransmission request may be repeated numerous times. When a vehicle is in motion, there may be circumstances which result in a wastage of slots for HARQ retransmissions that are not required by the vehicle. SUMMARY Disclosed herein is a system for managing communications in a vehicle. The system includes a telematics unit connected to the vehicle. The telematics unit is configured to execute a retransmission request protocol upon receipt of erroneous data. A command unit is in communication with the telematics unit, the command unit having a processor and tangible, non-transitory memory on which instructions are recorded. The command unit is adapted to determine vehicle situational parameters at a beginning of a data communication cycle. The vehicle situational parameters include current location and navigation status of the vehicle. The navigation status may include the past trajectory, the predicted or planned trajectory of the vehicle and speed. When a first retransmission according to the retransmission request protocol is detected, the vehicle situational parameters are updated. The command unit is adapted to determine a desirable value of a retransmission frequency for the retransmission request protocol based in part on the updated vehicle situational parameters. In one embodiment, the retransmission request protocol is Hybrid Automatic Repeat Request (HARQ). The command unit may be adapted to determine the desirable value for a response time based in part on the vehicle situational parameters, the response time being between receipt of the erroneous data and a response by the telematics unit. The vehicle situational parameters may include respective locations and respective signal strengths of one or more cellular towers within a predefined radius of the vehicle. In one embodiment, the command unit may be adapted to determine if an average data transfer rate required by a group of vehicles is above a predefined high threshold, the group having substantially similar downlink needs, where the vehicle is part of the group. The command unit may be adapted to designate a lead vehicle in the group to estimate lost code-block-groups (CBGs) for the group when the average data transfer rate for the group is above the predefined high threshold. The command unit may be adapted to employ preemptive estimates for the retransmission frequency for the lost code-block-groups (CBGs) when the average data transfer rate for the group is below the predefined high threshold. In another embodiment, the command unit may be adapted to determine if an average bit error rate for a group is greater than a predefined error rate threshold, where the vehicle is part of the group, the group having requirements for Enhanced Mobile Broadband applications and Ultra-Reliable Low Latency Communication (URLLC) applications. The command unit may be adapted to estimate the requirements for the Enhanced Mobile Broadband applications and the Ultra-Reliable Low Latency Communication (URLLC) applications for the group when the average bit error rate is greater than the predefined error rate threshold. The command unit may be adapted to reserve respective slots for the URLLC applications based on previous values of the retransmission frequency and a response time for the group. The command unit may be adapted to maximize switching of the respective slots from the Enhanced Mobile Broadband applications to the URLLC applications when the average bit error rate is less than or equal to the predefined error rate threshold. In another embodiment, the command unit may be adapted to select an uplink session for execution of a transmission time interval (TTI) bundling protocol defined by a TTI number, the TTI bundling protocol being adapted to permit data transfer in multiple consecutive sub-frames with a single acknowledgement signal for an entire bundle. The command unit may be adapted to determine if the uplink session is a low-latency application having a latency below a predefined latency threshold. The command unit may be adapted to select the TTI number to be relatively small when the latency is below the predefined latency threshold and select the TTI number to be relatively large when the latency is at or above the predefined latency threshold. Disclosed herein is a method of managing communications in a